diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,9 @@
+2022-04-07 Ivan Perez <ivan.perez@haskell.sexy>
+        * yampa-test.cabal: Version bump (0.13.4) (#203), syntax rules (#196),
+          add regression tests (#201).
+        * tests/YampaQC.hs: Remove incorrect tests (#198).
+        * tests/: Add regression tests (#201).
+
 2021-10-07 Ivan Perez <ivan.perez@keera.co.uk>
         * yampa-test.cabal: Version bump (0.13.3).
 
diff --git a/tests/Tests.hs b/tests/Tests.hs
new file mode 100644
--- /dev/null
+++ b/tests/Tests.hs
@@ -0,0 +1,191 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: Tests.hs,v 1.27 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         Tests                                            *
+*       Purpose:         regression tests.				     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+-- TODO:
+-- * Add test cases for Yampa. There should be at least one test case for each
+--   "non-trivial" entity exported from Yampa.
+--
+-- * Make tests cases for after and repeatedly more robust.  Must not
+--   fail due to small discrepancies in floating point implementation.
+--
+--   01-May-2002:  evsrc_t7 currently fails in hugs.
+--
+-- * Restructure test cases for papallel composition and switches to reflect
+--   Yampa structure better. Separate test cases for the generic definitions?
+-- There are some test cases for Utils. Not intended to be exhaustive.
+--
+-- VectorSpace has caused some ambiguity problems. See e.g. looplaws_t2,
+-- switch_t1a.
+--
+-- 2005-11-26: A simple way of making many test cases more robust would
+-- be to have a version of deltaEncode that adds a little extra time
+-- to the very first delta time. That way sampling would always be slightly
+-- "late".
+--
+-- But since we often compare time stamps, we'd also either have
+-- to adjust the "~=" relation to tolerate "jitter" of that magnitute,
+-- or we'd have to formulate many tests more carefully to allow a
+-- certain "fuzziness".
+
+module Tests where
+
+import FRP.Yampa
+
+import TestsCommon
+import TestsArr
+import TestsComp
+import TestsFirstSecond
+import TestsLaws
+import TestsLoop
+import TestsLoopLaws
+import TestsBasicSF
+import TestsSscan
+import TestsEvSrc
+import TestsCOC
+import TestsSwitch
+import TestsKSwitch
+import TestsRSwitch
+import TestsPSwitch
+import TestsRPSwitch
+import TestsWFG
+import TestsAccum
+import TestsPre
+import TestsDelay
+import TestsDer
+import TestsLoopPre
+import TestsLoopIntegral
+import TestsReact
+import TestsEmbed
+import TestsUtils
+import TestsTask
+
+
+------------------------------------------------------------------------------
+-- Global test and error reporting
+------------------------------------------------------------------------------
+
+allGood = arr_tr
+          && comp_tr
+          && first_tr
+          && second_tr
+          && laws_tr
+          && loop_tr
+          && looplaws_tr
+          && basicsf_tr
+          && sscan_tr
+          && evsrc_tr
+ 	  && coc_tr
+ 	  && switch_tr
+ 	  && kswitch_tr
+ 	  && rswitch_tr
+ 	  && pswitch_tr
+ 	  && rpswitch_tr
+ 	  && wfg_tr
+	  && accum_tr
+          && pre_tr
+ 	  && delay_tr
+	  && der_tr
+	  && loopPre_tr
+	  && loopIntegral_tr
+	  && react_tr
+	  && embed_tr
+	  && utils_tr
+	  && task_tr
+
+
+all_trs =
+    [ ("arr",          arr_trs),
+      ("comp",         comp_trs),
+      ("first",        first_trs),
+      ("second",       second_trs),
+      ("laws",         laws_trs),
+      ("loop",         loop_trs),
+      ("looplaws",     looplaws_trs),
+      ("basicsf",      basicsf_trs),
+      ("sscan",	       sscan_trs),
+      ("evsrc",        evsrc_trs),
+      ("coc",          coc_trs),
+      ("switch",       switch_trs),
+      ("kswitch",      kswitch_trs),
+      ("rswitch",      rswitch_trs),
+      ("pswitch",      pswitch_trs),
+      ("rpswitch",     rpswitch_trs),
+      ("wfg",	       wfg_trs),
+      ("accum",	       accum_trs),
+      ("pre",	       pre_trs),
+      ("delay",        delay_trs),
+      ("der",          der_trs),
+      ("loopPre",      loopPre_trs),
+      ("loopIntegral", loopIntegral_trs),
+      ("react",        react_trs),
+      ("embed",        embed_trs),
+      ("utils",        utils_trs),
+      ("task",         task_trs)
+    ]
+
+
+failedTests =
+    [ format n i | (n, trs) <- all_trs, (i, tr) <- zip [0..] trs, not tr ]
+    where
+	format n i = "Test " ++ n ++ "_t" ++ show i ++ " failed."
+
+
+runRegTests :: IO Bool
+runRegTests = do
+    putStrLn ""
+    putStrLn "Running the Yampa regression tests ..."
+    if allGood
+      then putStrLn "All tests succeeded!"
+      else mapM_ putStrLn failedTests
+    return allGood
+
+runSpaceTests :: IO ()
+runSpaceTests = do
+    putStrLn ""
+    putStrLn "Running the Yampa space tests ..."
+    putStrLn "Testing the space behaviour. This may take a LONG time."
+    putStrLn "Observe the process size using some tool like top."
+    putStrLn "The process should not grow significantly."
+    putStrLn "Emitted success/failure indications signify termination"
+    putStrLn "and whether or not the right result was obtained. They do"
+    putStrLn "not necessarily indicate that the space behaviour is correct"
+    putStrLn "(i.e., absence of leaks)."
+    putStrLn ""
+    rst "arr" 0 arr_st0 arr_st0r
+    rst "arr" 1 arr_st1 arr_st1r
+    rst "loop" 0 loop_st0 loop_st0r
+    rst "loop" 1 loop_st1 loop_st1r
+    rst "rswitch" 0 rswitch_st0 rswitch_st0r
+    rst "pswitch" 0 pswitch_st0 pswitch_st0r
+    rst "pswitch" 1 pswitch_st1 pswitch_st1r
+    rst "rpswitch" 0 rpswitch_st0 rpswitch_st0r
+    rst "accum" 0 accum_st0 accum_st0r
+    rst "accum" 1 accum_st1 accum_st1r
+    where
+	rst n i st str = do
+	    putStrLn ("Running " ++ n ++ "_st" ++ show i ++ " ...")
+	    if st ~= str then
+		putStrLn "Success!"
+	     else
+		-- We probably won't get here in case of a (space) failure ...
+		putStrLn "Failure!"
+
+-- AC: here because I had trouble running ghci:
+-- fixTest :: IO ()
+-- fixTest =
+--   let vs = loop_t17
+--   in putStrLn ("loop_t17 output: " ++ show vs)
+
+
+
diff --git a/tests/TestsAccum.hs b/tests/TestsAccum.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsAccum.hs
@@ -0,0 +1,361 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsAccum.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                   *
+*                                                                            *
+*       Module:         TestsAccum					     *
+*       Purpose:        Test cases for accumulators			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                           University of Nottingham, 2005                   *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsAccum (
+    accum_tr,
+    accum_trs,
+    accum_st0,
+    accum_st0r,
+    accum_st1,
+    accum_st1r
+) where
+
+import Data.Maybe (fromJust)
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for accumulators
+------------------------------------------------------------------------------
+
+accum_inp1 = (fromJust (head delta_inp), zip (repeat 1.0) (tail delta_inp))
+    where
+	delta_inp =
+	    [Just NoEvent, Nothing, Just (Event (+1.0)), Just NoEvent,
+	     Just (Event (+2.0)), Just NoEvent, Nothing, Nothing,
+	     Just (Event (*3.0)), Just (Event (+5.0)), Nothing, Just NoEvent,
+	     Just (Event (/2.0)), Just NoEvent, Nothing, Nothing]
+            ++ repeat Nothing
+
+accum_inp2 = (fromJust (head delta_inp), zip (repeat 1.0) (tail delta_inp))
+    where
+	delta_inp =
+	    [Just (Event (+1.0)), Just NoEvent, Nothing, Nothing,
+	     Just (Event (+2.0)), Just NoEvent, Nothing, Nothing,
+	     Just (Event (*3.0)), Just (Event (+5.0)), Nothing, Just NoEvent,
+	     Just (Event (/2.0)), Just NoEvent, Nothing, Nothing]
+            ++ repeat Nothing
+
+accum_inp3 = deltaEncode 1.0 $
+    [NoEvent,   NoEvent,   Event 1.0, NoEvent,
+     Event 2.0, NoEvent,   NoEvent,   NoEvent,
+     Event 3.0, Event 5.0, Event 5.0, NoEvent,
+     Event 0.0, NoEvent,   NoEvent,   NoEvent]
+    ++ repeat NoEvent
+
+accum_inp4 = deltaEncode 1.0 $
+    [Event 1.0, NoEvent,   NoEvent,   NoEvent,
+     Event 2.0, NoEvent,   NoEvent,   NoEvent,
+     Event 3.0, Event 5.0, Event 5.0, NoEvent,
+     Event 0.0, NoEvent,   NoEvent,   NoEvent]
+    ++ repeat NoEvent
+
+
+accum_inp5 = deltaEncode 0.25 (repeat ())
+
+
+accum_t0 :: [Event Double]
+accum_t0 = take 16 $ embed (accum 0.0) accum_inp1
+
+accum_t0r =
+    [NoEvent,   NoEvent,    Event 1.0,  NoEvent,
+     Event 3.0, NoEvent,    NoEvent,    NoEvent,
+     Event 9.0, Event 14.0, Event 19.0, NoEvent,
+     Event 9.5, NoEvent,    NoEvent,    NoEvent]
+
+
+accum_t1 :: [Event Double]
+accum_t1 = take 16 $ embed (accum 0.0) accum_inp2
+
+accum_t1r =
+    [Event 1.0, NoEvent,    NoEvent,    NoEvent,
+     Event 3.0, NoEvent,    NoEvent,    NoEvent,
+     Event 9.0, Event 14.0, Event 19.0, NoEvent,
+     Event 9.5, NoEvent,    NoEvent,    NoEvent]
+
+
+accum_t2 :: [Event Int]
+accum_t2 = take 16 $ embed (accumBy (\a d -> a + floor d) 0) accum_inp3
+
+accum_t2r :: [Event Int]
+accum_t2r =
+    [NoEvent,  NoEvent,  Event 1,  NoEvent,
+     Event 3,  NoEvent,  NoEvent,  NoEvent,
+     Event 6,  Event 11, Event 16, NoEvent,
+     Event 16, NoEvent,  NoEvent,  NoEvent]
+
+
+accum_t3 :: [Event Int]
+accum_t3 = take 16 $ embed (accumBy (\a d -> a + floor d) 0) accum_inp4
+
+accum_t3r :: [Event Int]
+accum_t3r =
+    [Event 1,  NoEvent,  NoEvent,  NoEvent,
+     Event 3,  NoEvent,  NoEvent,  NoEvent,
+     Event 6,  Event 11, Event 16, NoEvent,
+     Event 16, NoEvent,  NoEvent,  NoEvent]
+
+
+accum_accFiltFun1 a d =
+    let a' = a + floor d
+    in
+        if even a' then
+	    (a', Just (a' > 10, a'))
+        else
+	    (a', Nothing)
+
+accum_t4 :: [Event (Bool,Int)]
+accum_t4 = take 16 $ embed (accumFilter accum_accFiltFun1 0) accum_inp3
+
+accum_t4r :: [Event (Bool,Int)]
+accum_t4r =
+    [NoEvent,         NoEvent, NoEvent,         NoEvent,
+     NoEvent,         NoEvent, NoEvent,         NoEvent,
+     Event (False,6), NoEvent, Event (True,16), NoEvent,
+     Event (True,16), NoEvent, NoEvent,         NoEvent]
+
+
+accum_accFiltFun2 a d =
+    let a' = a + floor d
+    in
+        if odd a' then
+	    (a', Just (a' > 10, a'))
+        else
+	    (a', Nothing)
+
+accum_t5 :: [Event (Bool,Int)]
+accum_t5 = take 16 $ embed (accumFilter accum_accFiltFun2 0) accum_inp4
+
+accum_t5r :: [Event (Bool,Int)]
+accum_t5r =
+    [Event (False,1), NoEvent,         NoEvent, NoEvent,
+     Event (False,3), NoEvent,         NoEvent, NoEvent,
+     NoEvent,         Event (True,11), NoEvent, NoEvent,
+     NoEvent,         NoEvent,         NoEvent, NoEvent]
+
+
+-- This can be seen as the definition of accumFilter
+accumFilter2 :: (c -> a -> (c, Maybe b)) -> c -> SF (Event a) (Event b)
+accumFilter2 f c_init =
+    switch (never &&& attach c_init) afAux
+    where
+	afAux (c, a) =
+            case f c a of
+	        (c', Nothing) -> switch (never &&& (notYet>>>attach c')) afAux
+	        (c', Just b)  -> switch (now b &&& (notYet>>>attach c')) afAux
+
+	attach :: b -> SF (Event a) (Event (b, a))
+        attach c = arr (fmap (\a -> (c, a)))
+
+accum_t6 :: [Event (Bool,Int)]
+accum_t6 = take 16 $ embed (accumFilter2 accum_accFiltFun1 0) accum_inp3
+
+accum_t6r = accum_t4	-- Should agree!
+
+accum_t7 :: [Event (Bool,Int)]
+accum_t7 = take 16 $ embed (accumFilter2 accum_accFiltFun2 0) accum_inp4
+
+accum_t7r = accum_t5	-- Should agree!
+
+
+accum_t8 :: [Event Int]
+accum_t8 = take 40 $ embed (repeatedly 1.0 1
+                            >>> accumBy (+) 0
+                            >>> accumBy (+) 0)
+                           accum_inp5
+
+accum_t8r :: [Event Int]
+accum_t8r = [NoEvent,  NoEvent, NoEvent, NoEvent,
+             Event 1,  NoEvent, NoEvent, NoEvent,
+             Event 3,  NoEvent, NoEvent, NoEvent,
+             Event 6,  NoEvent, NoEvent, NoEvent,
+             Event 10, NoEvent, NoEvent, NoEvent,
+             Event 15, NoEvent, NoEvent, NoEvent,
+             Event 21, NoEvent, NoEvent, NoEvent,
+             Event 28, NoEvent, NoEvent, NoEvent,
+             Event 36, NoEvent, NoEvent, NoEvent,
+             Event 45, NoEvent, NoEvent, NoEvent]
+
+
+accum_t9 :: [Int]
+accum_t9 = take 40 $ embed (repeatedly 1.0 1
+                            >>> accumBy (+) 0
+                            >>> accumBy (+) 0
+                            >>> hold 0)
+                           accum_inp5
+
+accum_t9r :: [Int]
+accum_t9r = [0,0,0,0,1,1,1,1,3,3,3,3,6,6,6,6,10,10,10,10,15,15,15,15,
+             21,21,21,21,28,28,28,28,36,36,36,36,45,45,45,45]
+
+
+accum_t10 :: [Int]
+accum_t10 = take 40 $ embed (repeatedly 1.0 1
+                             >>> accumBy (+) 0
+                             >>> accumHoldBy (+) 0)
+                            accum_inp5
+
+accum_t10r :: [Int]
+accum_t10r = accum_t9	-- Should agree!
+
+
+accum_t11 :: [Int]
+accum_t11 = take 40 $ embed (repeatedly 1.0 1
+                             >>> accumBy (+) 0
+                             >>> accumBy (+) 0
+                             >>> dHold 0)
+                            accum_inp5
+
+accum_t11r :: [Int]
+accum_t11r = [0,0,0,0,0,1,1,1,1,3,3,3,3,6,6,6,6,10,10,10,10,15,15,15,
+              15,21,21,21,21,28,28,28,28,36,36,36,36,45,45,45]
+
+
+accum_t12 :: [Int]
+accum_t12 = take 40 $ embed (repeatedly 1.0 1
+                             >>> accumBy (+) 0
+                             >>> dAccumHoldBy (+) 0)
+                            accum_inp5
+
+accum_t12r :: [Int]
+accum_t12r = accum_t11	-- Should agree!
+
+
+accum_accFiltFun3 :: Int -> Int -> (Int, Maybe Int)
+accum_accFiltFun3 s a =
+    let s' = s + a
+    in
+        if odd s' then
+	    (s', Just s')
+        else
+	    (s', Nothing)
+
+
+accum_t13 :: [Event Int]
+accum_t13 = take 40 $ embed (repeatedly 1.0 1
+                            >>> accumFilter accum_accFiltFun3 0
+                            >>> accumBy (+) 0
+                            >>> accumBy (+) 0)
+                            accum_inp5
+
+accum_t13r :: [Event Int]
+accum_t13r = [NoEvent,  NoEvent, NoEvent, NoEvent,
+              Event 1,  NoEvent, NoEvent, NoEvent,
+              NoEvent,  NoEvent, NoEvent, NoEvent,
+              Event 5,  NoEvent, NoEvent, NoEvent,
+              NoEvent,  NoEvent, NoEvent, NoEvent,
+              Event 14, NoEvent, NoEvent, NoEvent,
+              NoEvent,  NoEvent, NoEvent, NoEvent,
+              Event 30, NoEvent, NoEvent, NoEvent,
+              NoEvent,  NoEvent, NoEvent, NoEvent,
+              Event 55, NoEvent, NoEvent, NoEvent]
+
+
+accum_t14 :: [Int]
+accum_t14 = take 40 $ embed (repeatedly 1.0 1
+                            >>> accumFilter accum_accFiltFun3 0
+                            >>> accumBy (+) 0
+                            >>> accumBy (+) 0
+                            >>> hold 0)
+                            accum_inp5
+
+accum_t14r :: [Int]
+accum_t14r = [0,0,0,0,1,1,1,1,1,1,1,1,5,5,5,5,5,5,5,5,14,14,14,14,
+              14,14,14,14,30,30,30,30,30,30,30,30,55,55,55,55]
+
+
+accum_t15 :: [Int]
+accum_t15 = take 40 $ embed (repeatedly 1.0 1
+                            >>> accumFilter accum_accFiltFun3 0
+                            >>> accumBy (+) 0
+                            >>> accumHoldBy (+) 0)
+                            accum_inp5
+
+accum_t15r :: [Int]
+accum_t15r = accum_t14	-- Should agree!
+
+
+accum_t16 :: [Int]
+accum_t16 = take 40 $ embed (repeatedly 1.0 1
+                            >>> accumFilter accum_accFiltFun3 0
+                            >>> accumBy (+) 0
+                            >>> accumBy (+) 0
+                            >>> dHold 0)
+                            accum_inp5
+
+accum_t16r :: [Int]
+accum_t16r = [0,0,0,0,0,1,1,1,1,1,1,1,1,5,5,5,5,5,5,5,5,14,14,14,
+              14,14,14,14,14,30,30,30,30,30,30,30,30,55,55,55]
+
+
+accum_t17 :: [Int]
+accum_t17 = take 40 $ embed (repeatedly 1.0 1
+                            >>> accumFilter accum_accFiltFun3 0
+                            >>> accumBy (+) 0
+                            >>> dAccumHoldBy (+) 0)
+                            accum_inp5
+
+accum_t17r :: [Int]
+accum_t17r = accum_t16	-- Should agree!
+
+
+
+accum_trs =
+    [ accum_t0  == accum_t0r,
+      accum_t1  == accum_t1r,
+      accum_t2  == accum_t2r,
+      accum_t3  == accum_t3r,
+      accum_t4  == accum_t4r,
+      accum_t5  == accum_t5r,
+      accum_t6  == accum_t6r,
+      accum_t7  == accum_t7r,
+      accum_t8  == accum_t8r,
+      accum_t9  == accum_t9r,
+      accum_t10 == accum_t10r,
+      accum_t11 == accum_t11r,
+      accum_t12 == accum_t12r,
+      accum_t13 == accum_t13r,
+      accum_t14 == accum_t14r,
+      accum_t15 == accum_t15r,
+      accum_t16 == accum_t16r,
+      accum_t17 == accum_t17r
+    ]
+
+accum_tr = and accum_trs
+
+
+accum_st0 :: Double
+accum_st0 = testSFSpaceLeak 1000000
+                            (repeatedly 1.0 1.0
+                             >>> accumBy (+) 0.0
+                             >>> hold (-99.99))
+
+accum_st0r = 249999.0
+
+
+accum_st1 :: Double
+accum_st1 = testSFSpaceLeak 1000000
+                            (arr dup
+			     >>> first (repeatedly 1.0 1.0)
+			     >>> arr (\(e,a) -> tag e a)
+                             >>> accumFilter accumFun 0.0
+                             >>> hold (-99.99))
+    where
+	accumFun c a | even (floor a) = (c+a, Just (c+a))
+		     | otherwise      = (c, Nothing)
+
+accum_st1r = 6.249975e10
diff --git a/tests/TestsArr.hs b/tests/TestsArr.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsArr.hs
@@ -0,0 +1,53 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsArr.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsArr                                             *
+*       Purpose:        Test cases for arr				     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsArr (
+    arr_trs,
+    arr_tr,
+    arr_st0,
+    arr_st0r,
+    arr_st1,
+    arr_st1r
+) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for arr
+------------------------------------------------------------------------------
+
+arr_t0 = testSF1 (arr (+1))
+arr_t0r =
+    [1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,15.0,16.0,
+     17.0,18.0,19.0,20.0,21.0,22.0,23.0,24.0,25.0]
+
+arr_t1 = testSF2 (arr (+1))
+arr_t1r =
+    [1.0,1.0,1.0,1.0,1.0,2.0,2.0,2.0,2.0,2.0,3.0,3.0,3.0,3.0,3.0,4.0,4.0,4.0,
+     4.0,4.0,5.0,5.0,5.0,5.0,5.0]
+
+arr_trs =
+    [ arr_t0 ~= arr_t0r,
+      arr_t1 ~= arr_t1r
+    ]
+
+arr_tr = and arr_trs
+
+arr_st0 = testSFSpaceLeak 2000000 (arr (+1))
+arr_st0r = 1000000.5
+
+arr_st1 = testSFSpaceLeak 2000000 identity
+arr_st1r = 999999.5
diff --git a/tests/TestsBasicSF.hs b/tests/TestsBasicSF.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsBasicSF.hs
@@ -0,0 +1,70 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsBasicSF.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsBasicSF				                         *
+*       Purpose:        Test cases for basic signal functions		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsBasicSF (basicsf_trs, basicsf_tr) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for basic signal functions and initialization
+------------------------------------------------------------------------------
+
+basicsf_t0 :: [Double]
+basicsf_t0 = testSF1 identity
+basicsf_t0r =
+    [0.0,  1.0,  2.0,  3.0,  4.0,  5.0,  6.0,  7.0,  8.0,  9.0,
+     10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0,
+     20.0, 21.0, 22.0, 23.0, 24.0]
+
+
+basicsf_t1 :: [Double]
+basicsf_t1 = testSF1 (constant 42.0)
+basicsf_t1r =
+    [42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0,
+     42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0,
+     42.0, 42.0, 42.0, 42.0, 42.0]
+
+basicsf_t2 :: [Double]
+basicsf_t2 = testSF1 localTime
+basicsf_t2r =
+    [0.0, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25,
+     2.5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75,
+     5.0, 5.25, 5.5, 5.75, 6.0]
+
+basicsf_t3 :: [Double]
+basicsf_t3 = testSF1 time
+basicsf_t3r =
+    [0.0, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25,
+     2.5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75,
+     5.0, 5.25, 5.5, 5.75, 6.0]
+
+basicsf_t4 :: [Double]
+basicsf_t4 = testSF1 (initially 42.0)
+basicsf_t4r =
+    [42.0, 1.0,  2.0,  3.0,  4.0,  5.0,  6.0,  7.0,  8.0,  9.0,
+     10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0,
+     20.0, 21.0, 22.0, 23.0, 24.0]
+
+
+basicsf_trs =
+    [ basicsf_t0 ~= basicsf_t0r,
+      basicsf_t1 ~= basicsf_t1r,
+      basicsf_t2 ~= basicsf_t2r,
+      basicsf_t3 ~= basicsf_t3r,
+      basicsf_t4 ~= basicsf_t4r
+    ]
+
+basicsf_tr = and basicsf_trs
diff --git a/tests/TestsCOC.hs b/tests/TestsCOC.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsCOC.hs
@@ -0,0 +1,57 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsCOC.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsCOC					                         *
+*       Purpose:        Test cases for collection-oriented combinators	     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsCOC (coc_tr, coc_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for collection-oriented combinators
+------------------------------------------------------------------------------
+
+coc_inp1 = deltaEncode 0.1 [0.0, 0.5 ..]
+
+coc_t0 :: [[Double]]
+coc_t0 = take 20 $ embed (parB [constant 1.0, identity, integral]) coc_inp1
+
+coc_t0r =
+    [[1.0, 0.0, 0.00],
+     [1.0, 0.5, 0.00],
+     [1.0, 1.0, 0.05],
+     [1.0, 1.5, 0.15],
+     [1.0, 2.0, 0.30],
+     [1.0, 2.5, 0.50],
+     [1.0, 3.0, 0.75],
+     [1.0, 3.5, 1.05],
+     [1.0, 4.0, 1.40],
+     [1.0, 4.5, 1.80],
+     [1.0, 5.0, 2.25],
+     [1.0, 5.5, 2.75],
+     [1.0, 6.0, 3.30],
+     [1.0, 6.5, 3.90],
+     [1.0, 7.0, 4.55],
+     [1.0, 7.5, 5.25],
+     [1.0, 8.0, 6.00],
+     [1.0, 8.5, 6.80],
+     [1.0, 9.0, 7.65],
+     [1.0, 9.5, 8.55]]
+
+
+coc_trs =
+    [ coc_t0 ~= coc_t0r
+    ]
+
+coc_tr = and coc_trs
diff --git a/tests/TestsCommon.hs b/tests/TestsCommon.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsCommon.hs
@@ -0,0 +1,170 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{-
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsCommon                                          *
+*       Purpose:        Common definitions for the regression test modules.  *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsCommon where
+
+import System.IO.Unsafe (unsafePerformIO)
+import Data.IORef (newIORef, writeIORef, readIORef)
+
+import FRP.Yampa
+
+------------------------------------------------------------------------------
+-- Rough equality with instances
+------------------------------------------------------------------------------
+
+-- Rough equality. Only intended to be good enough for test cases in this
+-- module.
+
+class REq a where
+    (~=) :: a -> a -> Bool
+
+epsilon :: Fractional a => a
+epsilon = 0.0001
+
+instance REq Float where
+    x ~= y = abs (x - y) < epsilon	-- A relative measure should be used.
+
+instance REq Double where
+    x ~= y = abs (x - y) < epsilon	-- A relative measure should be used.
+
+instance REq Int where
+    (~=) = (==)
+
+instance REq Integer where
+    (~=) = (==)
+
+instance REq Bool where
+    (~=) = (==)
+
+instance REq Char where
+    (~=) = (==)
+
+instance REq () where
+    () ~= () = True
+
+instance (REq a, REq b) => REq (a,b) where
+    (x1,x2) ~= (y1,y2) = x1 ~= y1 && x2 ~= y2
+
+instance (REq a, REq b, REq c) => REq (a,b,c) where
+    (x1,x2,x3) ~= (y1,y2,y3) = x1 ~= y1 && x2 ~= y2 && x3 ~= y3
+
+instance (REq a, REq b, REq c, REq d) => REq (a,b,c,d) where
+    (x1,x2,x3,x4) ~= (y1,y2,y3,y4) = x1 ~= y1
+				     && x2 ~= y2
+				     && x3 ~= y3
+				     && x4 ~= y4
+
+instance (REq a, REq b, REq c, REq d, REq e) => REq (a,b,c,d,e) where
+    (x1,x2,x3,x4,x5) ~= (y1,y2,y3,y4,y5) = x1 ~= y1
+				           && x2 ~= y2
+				           && x3 ~= y3
+				           && x4 ~= y4
+				           && x5 ~= y5
+
+instance REq a => REq (Maybe a) where
+    Nothing ~= Nothing   = True
+    (Just x) ~= (Just y) = x ~= y
+    _        ~= _        = False
+
+instance REq a => REq (Event a) where
+    NoEvent   ~= NoEvent   = True
+    (Event x) ~= (Event y) = x ~= y
+    _         ~= _         = False
+
+instance (REq a, REq b) => REq (Either a b) where
+    (Left x)  ~= (Left y)  = x ~= y
+    (Right x) ~= (Right y) = x ~= y
+    _         ~= _         = False
+
+instance REq a => REq [a] where
+    [] ~= []         = True
+    (x:xs) ~= (y:ys) = x ~= y && xs ~= ys
+    _      ~= _      = False
+
+
+------------------------------------------------------------------------------
+-- Testing utilities
+------------------------------------------------------------------------------
+
+testSF1 :: SF Double a -> [a]
+testSF1 sf = take 25 (embed sf (deltaEncodeBy (~=) 0.25 [0.0..]))
+
+
+testSF2 :: SF Double a -> [a]
+testSF2 sf = take 25 (embed sf (deltaEncodeBy (~=) 0.25 input))
+    where
+	-- The initial 0.0 is just for result compatibility with an older
+	-- version.
+	input = 0.0 : [ fromIntegral (b `div` freq) | b <- [1..] :: [Int] ]
+	freq = 5
+
+
+------------------------------------------------------------------------------
+-- Test harness for space behaviour
+------------------------------------------------------------------------------
+
+{-
+-- Test for space leaks.
+-- Carefully defined in an attempt to defeat fully lazy lambda lifting.
+-- Seems to work, but may be unsafe if the compiler decides to optimize
+-- aggressively.
+testSFSpaceLeak :: Int -> SF Double a -> a
+testSFSpaceLeak n sf = embed sf (deltaEncodeBy (~=) 0.25 [(seq n 0.0)..]) !! n
+-}
+
+
+-- Using embed/deltaEncode seems to be a bad idea since fully lazy
+-- lambda lifting often results in lifting a big input list to the top
+-- level in the form of a CAF. Using reactimate and avoiding constructing
+-- input/output lists should be more robust.
+
+testSFSpaceLeak :: Int -> SF Double a -> a
+testSFSpaceLeak n sf = unsafePerformIO $ do
+    countr  <- newIORef 0
+    inputr  <- newIORef undefined
+    outputr <- newIORef undefined
+    let init = do
+	    let input0 = 0.0
+            writeIORef inputr input0
+	    count <- readIORef countr
+	    writeIORef countr (count + 1)
+	    return input0
+        sense _ = do
+	    input <- readIORef inputr
+	    let input' = input + 0.5
+	    writeIORef inputr input'
+	    count <- readIORef countr
+	    writeIORef countr (count + 1)
+	    return (0.25, Just input')
+	actuate _ output = do
+	    writeIORef outputr output
+	    _input <- readIORef inputr
+	    count  <- readIORef countr
+	    return (count >= n)
+    reactimate init sense actuate sf
+
+    -- return output
+    readIORef outputr
+
+------------------------------------------------------------------------------
+-- Some utilities used for testing laws
+------------------------------------------------------------------------------
+
+fun_prod f g = \(x,y) -> (f x, g y)
+
+assoc :: ((a,b),c) -> (a,(b,c))
+assoc ((a,b),c) = (a,(b,c))
+
+assocInv :: (a,(b,c)) -> ((a,b),c)
+assocInv (a,(b,c)) = ((a,b),c)
diff --git a/tests/TestsComp.hs b/tests/TestsComp.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsComp.hs
@@ -0,0 +1,72 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsComp.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsComp					                         *
+*       Purpose:        Test cases for (>>>)				     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsComp (comp_tr, comp_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for comp
+------------------------------------------------------------------------------
+
+comp_t0 = testSF1 ((arr (+1)) >>> (arr (+2)))
+comp_t0r :: [Double]
+comp_t0r =
+    [3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,15.0,16.0,17.0,
+     18.0,19.0,20.0,21.0,22.0,23.0,24.0,25.0,26.0,27.0]
+
+comp_t1 = testSF2 ((arr (+1)) >>> (arr (+2)))
+comp_t1r :: [Double]
+comp_t1r =
+    [3.0,3.0,3.0,3.0,3.0,4.0,4.0,4.0,4.0,4.0,5.0,5.0,5.0,5.0,5.0,
+     6.0,6.0,6.0,6.0,6.0,7.0,7.0,7.0,7.0,7.0]
+
+comp_t2 = testSF1 ((constant 5.0) >>> (arr (+1)))
+comp_t2r :: [Double]
+comp_t2r =
+    [6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,
+     6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0]
+
+comp_t3 = testSF2 ((constant 5.0) >>> (arr (+1)))
+comp_t3r :: [Double]
+comp_t3r =
+    [6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,
+     6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0,6.0]
+
+-- Integration by the rectangle rule or trapezoid rule makes no difference.
+comp_t4 = testSF1 ((constant 2.0) >>> integral)
+comp_t4r :: [Double]
+comp_t4r =
+    [0.0,0.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0,4.5,5.0,5.5,6.0,6.5,7.0,7.5,8.0,8.5,
+     9.0,9.5,10.0,10.5,11.0,11.5,12.0]
+
+-- Same result as above.
+comp_t5 = testSF2 ((constant 2.0) >>> integral)
+comp_t5r :: [Double]
+comp_t5r =
+    [0.0,0.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0,4.5,5.0,5.5,6.0,6.5,7.0,7.5,8.0,8.5,
+     9.0,9.5,10.0,10.5,11.0,11.5,12.0]
+
+comp_trs =
+    [ comp_t0 ~= comp_t0r,
+      comp_t1 ~= comp_t1r,
+      comp_t2 ~= comp_t2r,
+      comp_t3 ~= comp_t3r,
+      comp_t4 ~= comp_t4r,
+      comp_t5 ~= comp_t5r
+    ]
+
+comp_tr = and comp_trs
diff --git a/tests/TestsDelay.hs b/tests/TestsDelay.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsDelay.hs
@@ -0,0 +1,89 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsDelay.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsDelay					                         *
+*       Purpose:        Test cases for delays				     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsDelay (delay_tr, delay_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for delays
+------------------------------------------------------------------------------
+
+delay_t0 = testSF1 (delay 0.0 undefined)
+delay_t0r =
+    [0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,
+     15.0,16.0,17.0,18.0,19.0,20.0,21.0,22.0,23.0,24.0]
+
+delay_t1 = testSF1 (delay 0.0001 17)
+delay_t1r =
+    [17.0,0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,
+     15.0,16.0,17.0,18.0,19.0,20.0,21.0,22.0,23.0]
+
+delay_t2 = testSF2 (delay 0.0001 17)
+delay_t2r =
+    [17.0,0.0,0.0,0.0,0.0,0.0,1.0,1.0,1.0,1.0,1.0,2.0,2.0,2.0,2.0,2.0,
+     3.0,3.0,3.0,3.0,3.0,4.0,4.0,4.0,4.0]
+
+delay_t3 = testSF1 (time
+                    >>> arr (\t -> sin (0.5 * t * pi + pi))
+                    >>> loop (arr (\(x1,x2) -> let x' = max x1 x2 in (x',x'))
+                              >>> second (delay 0.0001 0.0)))
+delay_t3r =
+    take 25
+         (let xs = [ sin (0.5 * t * pi + pi) | t <- [0.0, 0.25 ..] ]
+          in tail (scanl max 0 xs))
+
+dts_t4 = take 15 (repeat 0.1)
+         ++ [0.5, 0.5]
+         ++ take 15 (repeat 0.1)
+         ++ [2.0]
+         ++ take 20 (repeat 0.1)
+
+input_t4 = (0, [ (dt, Just i) | (dt, i) <- zip dts_t4 [1..] ])
+
+delay_t4, delay_t4r :: [Int]
+delay_t4 = take 100 (embed (delay 1.05 (-1)) input_t4)
+delay_t4r =
+    [ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	-- 0.0 s -- 0.9 s
+      -1,  0,  1,  2,  3,  4,			-- 1.0 s -- 1.5 s
+       9,                 14, 15, 15, 15, 15,	-- 2.0 s -- 2.9 s
+      15, 16, 16, 16, 16, 16, 17, 18, 19, 20,	-- 3.0 s -- 3.9 s
+      21,					-- 4.0 s
+      32, 32, 32, 32, 32, 32, 32, 32, 32, 32,	-- 6.0 s -- 6.9 s
+      32, 33, 34, 35, 36, 37, 38, 39, 40, 41,	-- 7.0 s -- 7.9 s
+      42					-- 8.0 s
+    ]
+
+
+delay_t5 = take 100 (drop 6 (embed sf (deltaEncode 0.1 (repeat ()))))
+    where
+        sf = time >>> arr (\t -> sin (2*pi*t)) >>> delay 0.55 (-1.0)
+
+delay_t5r = take 100 (drop 6 (embed sf (deltaEncode 0.1 (repeat ()))))
+    where
+        sf = time >>> arr (\t -> sin (2*pi*(t-0.6)))
+
+
+delay_trs =
+    [ delay_t0 ~= delay_t0r,
+      delay_t1 ~= delay_t1r,
+      delay_t2 ~= delay_t2r,
+      delay_t3 ~= delay_t3r,
+      delay_t4 == delay_t4r,
+      delay_t5 ~= delay_t5r
+    ]
+
+delay_tr = and delay_trs
diff --git a/tests/TestsDer.hs b/tests/TestsDer.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsDer.hs
@@ -0,0 +1,56 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsDer.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsDer					                         *
+*       Purpose:        Test cases for derivative			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsDer (der_tr, der_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for derivative
+------------------------------------------------------------------------------
+
+der_step = 0.001
+der_N = 1000
+
+der_t0 :: [Double]
+der_t0 = take der_N $	-- First value is always 0
+         embed derivative
+               (deltaEncode der_step
+			    [sin(2 * pi * t) | t <- [0.0, der_step ..]])
+{-
+-- For stepsize 0.1
+der_t0r :: [Double]
+der_t0r =
+    [ 0.0000,  5.8779,  3.6327, 0.0000, -3.6327,
+     -5.8779, -5.8779, -3.6327, 0.0000,  3.6327,
+      5.8779,  5.8779,  3.6327, 0.0000, -3.6327,
+     -5.8779, -5.8779, -3.6327, 0.0000,  3.6327]
+-}
+
+der_t0r :: [Double]
+der_t0r = take der_N $
+          [2 * pi * cos (2 * pi * t) | t <- [0.0, der_step ..]]
+
+-- We're happy if we are in the right ball park.
+der_t0_max_diff = (maximum (zipWith (\x y -> abs (x - y))
+                                    (tail der_t0)
+                                    (tail der_t0r)))
+
+der_trs =
+    [ der_t0_max_diff < 0.05
+    ]
+
+der_tr = and der_trs
diff --git a/tests/TestsEmbed.hs b/tests/TestsEmbed.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsEmbed.hs
@@ -0,0 +1,62 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsEmbed.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsEmbed					                         *
+*       Purpose:        Test cases for embedding			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsEmbed (embed_tr, embed_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for embedding
+------------------------------------------------------------------------------
+
+embed_ratio :: SF a Double
+embed_ratio = switch (constant 1.0 &&& after 5.0 ()) $ \_ ->
+	      switch (constant 0.0 &&& after 5.0 ()) $ \_ ->
+	      constant 3.0
+
+embed_sf :: SF a Double
+embed_sf = localTime >>> integral
+
+embed_t0 = take 20 $ embed (embed_ratio
+			    >>> embedSynch embed_sf
+					   (deltaEncode 0.01 (repeat ())))
+			   (deltaEncode 1.0 (repeat ()))
+
+embed_t0r =
+    [  0.0000,   0.4851,   1.9701,    4.4850,   7.9800,
+       7.9800,   7.9800,   7.9800,    7.9800,   7.9800,
+      24.4650,  49.9500,  84.4350,  127.9200, 180.2151,
+     241.6701, 312.1251, 391.5801, 480.03510, 577.4901]
+
+
+embed_t1 = take 20 $ embed (embed_ratio
+			    >>> embedSynch embed_sf
+					   (deltaEncode 0.5 (replicate 30 ())))
+			   (deltaEncode 1.0 (repeat ()))
+
+embed_t1r =
+    [   0.00,   0.25,   1.50,   3.75,   7.00,
+        7.00,   7.00,   7.00,   7.00,   7.00,
+       22.75,  47.50,  81.25, 101.50, 101.50,
+      101.50, 101.50, 101.50, 101.50, 101.50]
+
+embed_trs =
+    [ embed_t0 ~= embed_t0r,
+      embed_t1 ~= embed_t1r
+    ]
+
+
+embed_tr = and embed_trs
diff --git a/tests/TestsEvSrc.hs b/tests/TestsEvSrc.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsEvSrc.hs
@@ -0,0 +1,584 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsEvSrc.hs,v 1.3 2003/12/19 15:32:22 henrik Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsEvSrc					                         *
+*       Purpose:        Test cases for event sources			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsEvSrc (evsrc_trs, evsrc_tr) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for basic event sources and stateful event suppression
+------------------------------------------------------------------------------
+
+evsrc_t0 :: [Event ()]
+evsrc_t0 = testSF1 never
+
+evsrc_t0r =
+    [NoEvent, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t1 :: [Event Int]
+evsrc_t1 = testSF1 (now 42)
+
+evsrc_t1r :: [Event Int]
+evsrc_t1r =
+    [Event 42, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t2 :: [Event Int]
+evsrc_t2 = testSF1 (after 0.0 42)
+evsrc_t2r :: [Event Int]
+evsrc_t2r =
+    [Event 42, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t3 :: [Event Int]
+evsrc_t3 = testSF1 (after 3.0 42)
+
+evsrc_t3r :: [Event Int]
+evsrc_t3r =
+    [NoEvent,  NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     Event 42, NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t4 :: [Event Int]
+evsrc_t4 = testSF1 (after 3.01 42)
+
+evsrc_t4r :: [Event Int]
+evsrc_t4r =
+    [NoEvent, NoEvent,  NoEvent, NoEvent,	-- 0.0 s
+     NoEvent, NoEvent,  NoEvent, NoEvent,	-- 1.0 s
+     NoEvent, NoEvent,  NoEvent, NoEvent,	-- 2.0 s
+     NoEvent, Event 42, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent, NoEvent,  NoEvent, NoEvent,	-- 4.0 s
+     NoEvent, NoEvent,  NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t5 :: [Event Int]
+evsrc_t5 = testSF1 (repeatedly 0.795 42)
+
+evsrc_t5r :: [Event Int]
+evsrc_t5r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     Event 42, NoEvent,  NoEvent,  Event 42,	-- 1.0 s
+     NoEvent,  NoEvent,  Event 42, NoEvent,	-- 2.0 s
+     NoEvent,  Event 42, NoEvent,  NoEvent,	-- 3.0 s
+     Event 42, NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     Event 42, NoEvent,  NoEvent,  Event 42,	-- 5.0 s
+     NoEvent]
+
+evsrc_t6 :: [Event Int]
+evsrc_t6 = testSF1 (repeatedly 0.29999 42)
+
+evsrc_t6r :: [Event Int]
+evsrc_t6r =
+    [NoEvent,  NoEvent,  Event 42, Event 42,	-- 0.0 s
+     Event 42, Event 42, Event 42, NoEvent,	-- 1.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 2.0 s
+     Event 42, NoEvent,  Event 42, Event 42,	-- 3.0 s
+     Event 42, Event 42, Event 42, NoEvent,	-- 4.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 5.0 s
+     Event 42]
+
+evsrc_t7 :: [Event Int]
+evsrc_t7 = testSF1 (repeatedly 0.24 42)
+
+evsrc_t7r :: [Event Int]
+evsrc_t7r =
+    [NoEvent,  Event 42, Event 42, Event 42,	-- 0.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 1.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 2.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 3.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 4.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 5.0 s
+     Event 42]
+
+
+evsrc_t8 :: [Event Int]
+evsrc_t8 = testSF1 (afterEach [(0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4),
+                               (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8),
+			       (0.10, 9), (2.00, 10)])
+
+evsrc_t8r :: [Event Int]
+evsrc_t8r =
+    [Event 1,  Event 3,  Event 5,  NoEvent,	-- 0.0 s
+     NoEvent,  Event 6,  Event 9,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  Event 10, NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t9 :: [Event Int]
+evsrc_t9 = testSF1 (afterEach [(2.03, 0),
+			       (0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4),
+                               (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8),
+			       (0.10, 9), (2.00, 10), (0.00, 11), (0.00, 12)])
+
+evsrc_t9r :: [Event Int]
+evsrc_t9r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  Event 0,  Event 4,  NoEvent,	-- 2.0 s
+     NoEvent,  Event 6,  Event 9,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  Event 10, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+
+evsrc_t10 :: [Event [Int]]
+evsrc_t10 = testSF1 (afterEachCat [(0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4),
+                                   (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8),
+			           (0.10, 9), (2.00, 10)])
+
+evsrc_t10r :: [Event [Int]]
+evsrc_t10r =
+    [Event [1,2],  Event [3,4],    Event [5],  NoEvent,	-- 0.0 s
+     NoEvent,      Event [6,7,8],  Event [9],  NoEvent,	-- 1.0 s
+     NoEvent,      NoEvent,        NoEvent,    NoEvent,	-- 2.0 s
+     NoEvent,      NoEvent,        Event [10], NoEvent,	-- 3.0 s
+     NoEvent,      NoEvent,        NoEvent,    NoEvent,	-- 4.0 s
+     NoEvent,      NoEvent,        NoEvent,    NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t11 :: [Event [Int]]
+evsrc_t11 = testSF1 (afterEachCat [(2.03, 0),
+			           (0.00, 1), (0.00, 2), (0.01, 3), (0.23, 4),
+                                   (0.02, 5), (0.75, 6), (0.10, 7), (0.10, 8),
+			           (0.10, 9), (2.00, 10)])
+
+evsrc_t11r :: [Event [Int]]
+evsrc_t11r =
+    [NoEvent,  NoEvent,         NoEvent,     NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,         NoEvent,     NoEvent,	-- 1.0 s
+     NoEvent,  Event [0,1,2,3], Event [4,5], NoEvent,	-- 2.0 s
+     NoEvent,  Event [6,7,8],   Event [9],   NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,         NoEvent,     NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,         Event [10],  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t12 :: [Event ()]
+evsrc_t12 = testSF1 (localTime >>> arr (>=0) >>> edge)
+
+evsrc_t12r =
+    [NoEvent, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent,	NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, NoEvent,	NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent,	NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t13 :: [Event ()]
+evsrc_t13 = testSF1 (localTime >>> arr (>=4.26) >>> edge)
+
+evsrc_t13r =
+    [NoEvent, NoEvent, NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, Event (), NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+-- Raising edge detector.
+evsrc_isEdge False False = Nothing
+evsrc_isEdge False True  = Just ()
+evsrc_isEdge True  True  = Nothing
+evsrc_isEdge True  False = Nothing
+
+
+evsrc_t14 :: [Event ()]
+evsrc_t14 = testSF1 (localTime >>> arr (>=0) >>> edgeBy evsrc_isEdge False)
+
+evsrc_t14r =
+    [Event (), NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+evsrc_t15 :: [Event ()]
+evsrc_t15 = testSF1 (localTime >>> arr (>=4.26) >>> edgeBy evsrc_isEdge False)
+
+evsrc_t15r =
+    [NoEvent, NoEvent, NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, Event (), NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 5.0 s
+     NoEvent]
+
+-- Raising and falling edge detector.
+evsrc_isEdge2 False False = Nothing
+evsrc_isEdge2 False True  = Just True
+evsrc_isEdge2 True  True  = Nothing
+evsrc_isEdge2 True  False = Just False
+
+evsrc_t16 :: [Event Bool]
+evsrc_t16 = testSF1 (localTime
+                    >>> arr (\t -> t >=2.01 && t <= 4.51)
+		    >>> edgeBy evsrc_isEdge2 True)
+
+evsrc_t16r =
+    [Event False, NoEvent,    NoEvent, NoEvent,		-- 0.0 s
+     NoEvent,     NoEvent,    NoEvent, NoEvent,		-- 1.0 s
+     NoEvent,     Event True, NoEvent, NoEvent,		-- 2.0 s
+     NoEvent,     NoEvent,    NoEvent, NoEvent,		-- 3.0 s
+     NoEvent,     NoEvent,    NoEvent, Event False,	-- 4.0 s
+     NoEvent,     NoEvent,    NoEvent, NoEvent,		-- 5.0 s
+     NoEvent]
+
+evsrc_t17 :: [Event Int]
+evsrc_t17 = testSF1 (now 17 &&& repeatedly 0.795 42
+		     >>> arr (uncurry merge)
+		     >>> notYet)
+
+evsrc_t17r :: [Event Int]
+evsrc_t17r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     Event 42, NoEvent,  NoEvent,  Event 42,	-- 1.0 s
+     NoEvent,  NoEvent,  Event 42, NoEvent,	-- 2.0 s
+     NoEvent,  Event 42, NoEvent,  NoEvent,	-- 3.0 s
+     Event 42, NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     Event 42, NoEvent,  NoEvent,  Event 42,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t18 :: [Event Int]
+evsrc_t18 = testSF1 (now 42 >>> once)
+
+evsrc_t18r :: [Event Int]
+evsrc_t18r =
+    [Event 42, NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t19 :: [Event Int]
+evsrc_t19 = testSF1 (repeatedly 0.8 42 >>> once)
+
+evsrc_t19r :: [Event Int]
+evsrc_t19r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     Event 42, NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t20 :: [Event Int]
+evsrc_t20 = testSF1 (now 42 >>> takeEvents 0)
+
+evsrc_t20r :: [Event Int]
+evsrc_t20r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t21 :: [Event Int]
+evsrc_t21 = testSF1 (now 42 >>> takeEvents 1)
+
+evsrc_t21r :: [Event Int]
+evsrc_t21r =
+    [Event 42, NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t22 :: [Event Int]
+evsrc_t22 = testSF1 (repeatedly 0.8 42 >>> takeEvents 4)
+
+evsrc_t22r :: [Event Int]
+evsrc_t22r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     Event 42, NoEvent,  NoEvent,  Event 42,	-- 1.0 s
+     NoEvent,  NoEvent,  Event 42, NoEvent,	-- 2.0 s
+     NoEvent,  Event 42, NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t23 :: [Event Int]
+evsrc_t23 = testSF1 (repeatedly 0.2 42 >>> takeEvents 4)
+
+evsrc_t23r :: [Event Int]
+evsrc_t23r =
+    [NoEvent,  Event 42, Event 42, Event 42,	-- 0.0 s
+     Event 42, NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t24 :: [Event Int]
+evsrc_t24 = testSF1 (now 42 >>> dropEvents 0)
+
+evsrc_t24r :: [Event Int]
+evsrc_t24r =
+    [Event 42, NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t25 :: [Event Int]
+evsrc_t25 = testSF1 (now 42 >>> dropEvents 1)
+
+evsrc_t25r :: [Event Int]
+evsrc_t25r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t26 :: [Event Int]
+-- Drop 5 events to get rid of the event at 4.0 s which may or may not happen
+-- exactly there.
+evsrc_t26 = testSF1 (repeatedly 0.8 42 >>> dropEvents 5)
+
+evsrc_t26r :: [Event Int]
+evsrc_t26r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 4.0 s
+     Event 42, NoEvent,  NoEvent,  Event 42,	-- 5.0 s
+     NoEvent]
+
+
+evsrc_t27 :: [Event Int]
+evsrc_t27 = testSF1 (repeatedly 0.2 42 >>> dropEvents 4)
+
+evsrc_t27r :: [Event Int]
+evsrc_t27r =
+    [NoEvent,  NoEvent,  NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent,  Event 42, Event 42, Event 42,	-- 1.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 2.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 3.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 4.0 s
+     Event 42, Event 42, Event 42, Event 42,	-- 5.0 s
+     Event 42]
+
+
+
+evsrc_t28 :: [(Event Int, Event Int)]
+evsrc_t28 = embed (repeatedly 0.5 ()
+                   >>> accumBy (\n _ -> n + 1) 0
+                   >>> identity &&& delayEvent 2.0)
+                  (deltaEncode 0.125 (replicate 50 ()))
+
+evsrc_t28r =
+    [ (NoEvent,NoEvent),  (NoEvent,NoEvent),	-- 0.0 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 1,NoEvent),  (NoEvent,NoEvent),	-- 0.5 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 2,NoEvent),  (NoEvent,NoEvent),	-- 1.0 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 3,NoEvent),  (NoEvent,NoEvent),	-- 1.5 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 4,NoEvent),  (NoEvent,NoEvent),	-- 2.0 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 5,Event 1),  (NoEvent,NoEvent),	-- 2.5 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 6,Event 2),  (NoEvent,NoEvent),	-- 3.0 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 7,Event 3),  (NoEvent,NoEvent),	-- 3.5 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 8,Event 4),  (NoEvent,NoEvent),	-- 4.0 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 9,Event 5),  (NoEvent,NoEvent),	-- 4.5 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 10,Event 6), (NoEvent,NoEvent),	-- 5.0 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 11,Event 7), (NoEvent,NoEvent),	-- 5.5 s
+      (NoEvent,NoEvent),  (NoEvent,NoEvent),
+      (Event 12,Event 8), (NoEvent,NoEvent)	-- 6.0 s
+    ]
+
+evsrc_t29 :: [Event [Double]]
+evsrc_t29 = embed (time &&& repeatedly 0.5001 ()
+                   >>> arr (\(t,e) -> e `tag` t)
+                   >>> delayEventCat 3.0)
+                  input
+    where
+        dts   = replicate 40 0.1 ++ [2.0] ++ replicate 40 0.1
+	input = ((), [(dt, Just ()) | dt <- dts])
+
+{- Resulting input to the delay for reference:
+[ NoEvent,   NoEvent,   NoEvent, NoEvent, NoEvent,	-- 0.0 s
+  NoEvent,   Event 0.6, NoEvent, NoEvent, NoEvent,	-- 0.5 s
+  NoEvent,   Event 1.1, NoEvent, NoEvent, NoEvent,	-- 1.0 s
+  NoEvent,   Event 1.6, NoEvent, NoEvent, NoEvent,	-- 1.5 s
+  NoEvent,   Event 2.1, NoEvent, NoEvent, NoEvent,	-- 2.0 s
+  NoEvent,   Event 2.6, NoEvent, NoEvent, NoEvent,	-- 2.5 s
+  NoEvent,   Event 3.1, NoEvent, NoEvent, NoEvent,	-- 3.0 s
+  NoEvent,   Event 3.6, NoEvent, NoEvent, NoEvent,	-- 3.5 s
+  NoEvent,						-- 4.0 s
+  Event 6.0, Event 6.1, NoEvent, NoEvent, NoEvent,	-- 6.0 s
+  NoEvent,   Event 6.6, NoEvent, NoEvent, NoEvent,	-- 6.5 s
+  NoEvent,   Event 7.1, NoEvent, NoEvent, NoEvent,	-- 7.0 s
+  NoEvent,   Event 7.6, NoEvent, NoEvent, NoEvent,	-- 7.5 s
+  NoEvent,   Event 8.1, NoEvent, NoEvent, NoEvent,	-- 8.0 s
+  NoEvent,   Event 8.6, NoEvent, NoEvent, NoEvent,	-- 8.5 s
+  NoEvent,   Event 9.1, NoEvent, NoEvent, NoEvent,	-- 9.0 s
+  NoEvent,   Event 9.6, NoEvent, NoEvent, NoEvent,	-- 9.5 s
+  NoEvent ]						-- 10.0 s
+-}
+
+evsrc_t29r =
+    [ NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent,		-- 0.0 s
+      NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent,		-- 0.5 s
+      NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent,		-- 1.0 s
+      NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent,		-- 1.5 s
+      NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent,		-- 2.0 s
+      NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent,		-- 2.5 s
+      NoEvent, NoEvent,     NoEvent, NoEvent, NoEvent,		-- 3.0 s
+      NoEvent, Event [0.6], NoEvent, NoEvent, NoEvent,		-- 3.5 s
+      NoEvent,							-- 4.0 s
+      Event [1.1, 1.6, 2.1, 2.6],				-- 6.0 s
+          NoEvent, Event [3.1], NoEvent, NoEvent,
+      NoEvent, NoEvent,     Event [3.6], NoEvent, NoEvent,	-- 6.5 s
+      NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent,	-- 7.0 s
+      NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent,	-- 7.5 s
+      NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent,	-- 8.0 s
+      NoEvent, NoEvent,     NoEvent,     NoEvent, NoEvent,	-- 8.5 s
+      NoEvent, Event [6.0], Event [6.1], NoEvent, NoEvent,	-- 9.0 s
+      NoEvent, NoEvent,     Event [6.6], NoEvent, NoEvent,	-- 9.5 s
+      NoEvent							-- 10.0 s
+    ]
+
+-- "delayEvent" in a feedback loop. Should work like "repeatedly".
+evsrc_t30 :: [(Event ())]
+evsrc_t30 = embed (now ()
+                   >>> (loop $
+			    arr (uncurry lMerge)
+                            >>> delayEvent 1.0
+                            >>> arr dup))
+                  (deltaEncode 0.125 (replicate 50 ()))
+
+
+evsrc_t30r :: [(Event ())]
+evsrc_t30r =
+    [ NoEvent,  NoEvent, NoEvent, NoEvent,	-- 0.0 s
+      NoEvent,  NoEvent, NoEvent, NoEvent,	-- 0.5 s
+      Event (), NoEvent, NoEvent, NoEvent, 	-- 1.0 s
+      NoEvent,  NoEvent, NoEvent, NoEvent,	-- 1.5 s
+      Event (), NoEvent, NoEvent, NoEvent,	-- 2.0 s
+      NoEvent,  NoEvent, NoEvent, NoEvent,	-- 2.5 s
+      Event (), NoEvent, NoEvent, NoEvent,	-- 3.0 s
+      NoEvent,  NoEvent, NoEvent, NoEvent,	-- 3.5 s
+      Event (), NoEvent, NoEvent, NoEvent,	-- 4.0 s
+      NoEvent,  NoEvent, NoEvent, NoEvent,	-- 4.5 s
+      Event (), NoEvent, NoEvent, NoEvent,	-- 5.0 s
+      NoEvent,  NoEvent, NoEvent, NoEvent,	-- 5.5 s
+      Event (), NoEvent				-- 6.0 s
+    ]
+
+
+evsrc_trs =
+    [ evsrc_t0 ~= evsrc_t0r,
+      evsrc_t1 ~= evsrc_t1r,
+      evsrc_t2 ~= evsrc_t2r,
+      evsrc_t3 ~= evsrc_t3r,
+      evsrc_t4 ~= evsrc_t4r,
+      evsrc_t5 ~= evsrc_t5r,
+      evsrc_t6 ~= evsrc_t6r,
+      evsrc_t7 ~= evsrc_t7r,
+      evsrc_t8 ~= evsrc_t8r,
+      evsrc_t9 ~= evsrc_t9r,
+      evsrc_t10 ~= evsrc_t10r,
+      evsrc_t11 ~= evsrc_t11r,
+      evsrc_t12 ~= evsrc_t12r,
+      evsrc_t13 ~= evsrc_t13r,
+      evsrc_t14 ~= evsrc_t14r,
+      evsrc_t15 ~= evsrc_t15r,
+      evsrc_t16 ~= evsrc_t16r,
+      evsrc_t17 ~= evsrc_t17r,
+      evsrc_t18 ~= evsrc_t18r,
+      evsrc_t19 ~= evsrc_t19r,
+      evsrc_t20 ~= evsrc_t20r,
+      evsrc_t21 ~= evsrc_t21r,
+      evsrc_t22 ~= evsrc_t22r,
+      evsrc_t23 ~= evsrc_t23r,
+      evsrc_t24 ~= evsrc_t24r,
+      evsrc_t25 ~= evsrc_t25r,
+      evsrc_t26 ~= evsrc_t26r,
+      evsrc_t27 ~= evsrc_t27r,
+      evsrc_t28 ~= evsrc_t28r,
+      evsrc_t29 ~= evsrc_t29r,
+      evsrc_t30 ~= evsrc_t30r
+    ]
+
+evsrc_tr = and evsrc_trs
diff --git a/tests/TestsFirstSecond.hs b/tests/TestsFirstSecond.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsFirstSecond.hs
@@ -0,0 +1,128 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsFirstSecond.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsArr                                             *
+*       Purpose:        Test cases for first and second			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsFirstSecond (first_trs, first_tr, second_trs, second_tr) where
+
+import Data.Tuple (swap)
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for first
+------------------------------------------------------------------------------
+
+first_t0 :: [(Int,Double)]
+first_t0 = testSF1 (arr dup >>> first (constant 7))
+first_t0r :: [(Int,Double)]
+first_t0r =
+    [(7,0.0),  (7,1.0),  (7,2.0),  (7,3.0),  (7,4.0),
+     (7,5.0),  (7,6.0),  (7,7.0),  (7,8.0),  (7,9.0),
+     (7,10.0), (7,11.0), (7,12.0), (7,13.0), (7,14.0),
+     (7,15.0), (7,16.0), (7,17.0), (7,18.0), (7,19.0),
+     (7,20.0), (7,21.0), (7,22.0), (7,23.0), (7,24.0)]
+
+first_t1 :: [(Int,Double)]
+first_t1 = testSF2 (arr dup >>> first (constant 7))
+first_t1r :: [(Int,Double)]
+first_t1r =
+    [(7,0.0), (7,0.0), (7,0.0), (7,0.0), (7,0.0),
+     (7,1.0), (7,1.0), (7,1.0), (7,1.0), (7,1.0),
+     (7,2.0), (7,2.0), (7,2.0), (7,2.0), (7,2.0),
+     (7,3.0), (7,3.0), (7,3.0), (7,3.0), (7,3.0),
+     (7,4.0), (7,4.0), (7,4.0), (7,4.0), (7,4.0)]
+
+first_t2 :: [(Double,Double)]
+first_t2 = testSF1 (arr dup >>> first (arr (+1)))
+first_t2r =
+    [(1.0,0.0),   (2.0,1.0),   (3.0,2.0),   (4.0,3.0),   (5.0,4.0),
+     (6.0,5.0),   (7.0,6.0),   (8.0,7.0),   (9.0,8.0),   (10.0,9.0),
+     (11.0,10.0), (12.0,11.0), (13.0,12.0), (14.0,13.0), (15.0,14.0),
+     (16.0,15.0), (17.0,16.0), (18.0,17.0), (19.0,18.0), (20.0,19.0),
+     (21.0,20.0), (22.0,21.0), (23.0,22.0), (24.0,23.0), (25.0,24.0)]
+
+first_t3 :: [(Double,Double)]
+first_t3 = testSF2 (arr dup >>> first (arr (+1)))
+first_t3r =
+    [(1.0,0.0), (1.0,0.0), (1.0,0.0), (1.0,0.0), (1.0,0.0),
+     (2.0,1.0), (2.0,1.0), (2.0,1.0), (2.0,1.0), (2.0,1.0),
+     (3.0,2.0), (3.0,2.0), (3.0,2.0), (3.0,2.0), (3.0,2.0),
+     (4.0,3.0), (4.0,3.0), (4.0,3.0), (4.0,3.0), (4.0,3.0),
+     (5.0,4.0), (5.0,4.0), (5.0,4.0), (5.0,4.0), (5.0,4.0)]
+
+first_t4 :: [(Double,Double)]
+first_t4 = testSF1 (arr dup >>> first integral)
+first_t4r =
+    [(0.0,0.0),    (0.0,1.0),    (0.25,2.0),   (0.75,3.0),   (1.5,4.0),
+     (2.5,5.0),    (3.75,6.0),   (5.25,7.0),   (7.0,8.0),    (9.0,9.0),
+     (11.25,10.0), (13.75,11.0), (16.5,12.0),  (19.5,13.0),  (22.75,14.0),
+     (26.25,15.0), (30.0,16.0),  (34.0,17.0),  (38.25,18.0), (42.75,19.0),
+     (47.5,20.0),  (52.5,21.0),  (57.75,22.0), (63.25,23.0), (69.0,24.0)]
+
+first_t5 :: [(Double,Double)]
+first_t5 = testSF2 (arr dup >>> first integral)
+first_t5r =
+    [(0.0,0.0),  (0.0,0.0),  (0.0,0.0),  (0.0,0.0),  (0.0,0.0),
+     (0.0,1.0),  (0.25,1.0), (0.5,1.0),  (0.75,1.0), (1.0,1.0),
+     (1.25,2.0), (1.75,2.0), (2.25,2.0), (2.75,2.0), (3.25,2.0),
+     (3.75,3.0), (4.5,3.0),  (5.25,3.0), (6.0,3.0),  (6.75,3.0),
+     (7.5,4.0),  (8.5,4.0),  (9.5,4.0),  (10.5,4.0), (11.5,4.0)]
+
+first_trs =
+    [ first_t0 ~= first_t0r,
+      first_t1 ~= first_t1r,
+      first_t2 ~= first_t2r,
+      first_t3 ~= first_t3r,
+      first_t4 ~= first_t4r,
+      first_t5 ~= first_t5r
+    ]
+
+first_tr = and first_trs
+
+
+------------------------------------------------------------------------------
+-- Test cases for second
+------------------------------------------------------------------------------
+
+-- These should mirror the test cases for first.
+
+second_t0 :: [(Int,Double)]
+second_t0 = testSF1 (arr dup >>> second (constant 7) >>> arr swap)
+
+second_t1 :: [(Int,Double)]
+second_t1 = testSF2 (arr dup >>> second (constant 7) >>> arr swap)
+
+second_t2 :: [(Double,Double)]
+second_t2 = testSF1 (arr dup >>> second (arr (+1)) >>> arr swap)
+
+second_t3 :: [(Double,Double)]
+second_t3 = testSF2 (arr dup >>> second (arr (+1)) >>> arr swap)
+
+second_t4 :: [(Double,Double)]
+second_t4 = testSF1 (arr dup >>> second integral >>> arr swap)
+
+second_t5 :: [(Double,Double)]
+second_t5 = testSF2 (arr dup >>> second integral >>> arr swap)
+
+second_trs =
+    [ second_t0 ~= first_t0r,
+      second_t1 ~= first_t1r,
+      second_t2 ~= first_t2r,
+      second_t3 ~= first_t3r,
+      second_t4 ~= first_t4r,
+      second_t5 ~= first_t5r
+    ]
+
+second_tr = and second_trs
diff --git a/tests/TestsKSwitch.hs b/tests/TestsKSwitch.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsKSwitch.hs
@@ -0,0 +1,129 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsKSwitch.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsKSwitch				                         *
+*       Purpose:        Test cases for kSwitch and dkSwitch		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsKSwitch (kswitch_tr, kswitch_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for kSwitch and dkSwitch
+------------------------------------------------------------------------------
+
+kswitch_inp1 = deltaEncode 0.1 [0.0, 0.5 ..]
+
+whenSndGE :: Ord b => b -> c -> SF (a, b) (Event c)
+whenSndGE b c = arr snd >>> arr (>= b) >>> edge >>> arr (`tag` c)
+
+
+kswitch_t0 :: [Double]
+kswitch_t0 = take 20 $ embed sf kswitch_inp1
+    where
+	sf =
+	    kSwitch integral (whenSndGE 0.2 (-1.0)) $ \sf1 x ->
+	    kSwitch (integral >>> arr (+x)) (whenSndGE 1.0 (1.0)) $ \_ _ ->
+            sf1
+
+kswitch_t0r =
+    [ 0.00,  0.00,  0.05, 0.15, -1.00,
+     -0.80, -0.55, -0.25, 0.10,  0.50,
+      0.95,  0.30,  0.85, 1.45,  2.10,
+      2.80,  3.55,  4.35, 5.20,  6.10]
+
+
+kswitch_t1 :: [Double]
+kswitch_t1 = take 20 $ embed sf kswitch_inp1
+    where
+	sf =
+	    dkSwitch integral (whenSndGE 0.2 (-1.0)) $ \sf1 x ->
+	    dkSwitch (integral >>> arr (+x)) (whenSndGE 1.0 (1.0)) $ \_ _ ->
+            sf1
+
+kswitch_t1r =
+    [ 0.00,  0.00,  0.05, 0.15, 0.30,
+     -0.80, -0.55, -0.25, 0.10, 0.50,
+      0.95,  1.45,  0.85, 1.45, 2.10,
+      2.80,  3.55,  4.35, 5.20, 6.10]
+
+
+kswitch_t2 :: [Double]
+kswitch_t2 = take 20 $ embed sf kswitch_inp1
+    where
+	sf =
+	    kSwitch integral (now (-1.0)) $ \sf1 x ->
+	    kSwitch (integral >>> arr (+x)) (whenSndGE 1.0 (1.0)) $ \_ _ ->
+            sf1
+
+kswitch_t2r =
+    [-1.00, -1.00, -0.95, -0.85, -0.70,
+     -0.50, -0.25,  0.05,  0.40,  0.80,
+      0.00,  0.50,  1.05,  1.65,  2.30,
+      3.00,  3.75,  4.55,  5.40,  6.30]
+
+
+kswitch_t3 :: [Double]
+kswitch_t3 = take 20 $ embed sf kswitch_inp1
+    where
+	sf =
+	    dkSwitch integral (now (-1.0)) $ \sf1 x ->
+	    dkSwitch (integral >>> arr (+x)) (whenSndGE 1.0 (1.0)) $ \_ _ ->
+            sf1
+
+kswitch_t3r =
+    [ 0.00, -1.00, -0.95, -0.85, -0.70,
+     -0.50, -0.25,  0.05,  0.40,  0.80,
+      1.25,  0.50,  1.05,  1.65,  2.30,
+      3.00,  3.75,  4.55,  5.40,  6.30]
+
+
+-- The correct strictness properties of dkSwitch are crucial here.
+-- kSwitch does not work.
+kswitch_t4 = take 40 $
+    embed (loop $
+	       dkSwitch sf (sfe 0.55 (-1.0))              $ \sf1 x ->
+	       dkSwitch (sf >>> arr2 (+x)) (sfe 0.05 8.0) $ \sf2 y ->
+	       dkSwitch sf1 (sfe 2.0 (-2.0))              $ \_   z ->
+	       sf2 >>> arr2 (+(y + z))
+           )
+          (deltaEncode 0.1 (repeat ()))
+    where
+        sf :: SF (a, Double) (Double, Double)
+        sf = constant 1.0 >>> integral >>> arr dup
+
+	sfe :: Double -> Double -> SF ((a, Double), b) (Event Double)
+	sfe x e = arr fst >>> whenSndGE x e
+
+	arr2 f = arr (\(x,y) -> (f x, f y))
+
+kswitch_t4r =
+    [ 0.0,  0.1,  0.2,  0.3,  0.4,
+      0.5,  0.6, -0.9, -0.8, -0.7,
+     -0.6, -0.5, -0.4, -0.3, -0.2,
+     -0.1,  0.0,  0.1,  0.7,  0.8,
+      0.9,  1.0,  1.1,  1.2,  1.3,
+      1.4,  1.5,  1.6,  1.7,  1.8,
+      1.9,  2.0,  6.2,  6.3,  6.4,
+      6.5,  6.6,  6.7,  6.8,  6.9]
+
+
+kswitch_trs =
+    [ kswitch_t0 ~= kswitch_t0r,
+      kswitch_t1 ~= kswitch_t1r,
+      kswitch_t2 ~= kswitch_t2r,
+      kswitch_t3 ~= kswitch_t3r,
+      kswitch_t4 ~= kswitch_t4r
+    ]
+
+kswitch_tr = and kswitch_trs
diff --git a/tests/TestsLaws.hs b/tests/TestsLaws.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsLaws.hs
@@ -0,0 +1,90 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsLaws.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsLaws                                            *
+*       Purpose:        Test cases based on the arrow laws		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsLaws (laws_trs, laws_tr) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases based on the arrow laws
+------------------------------------------------------------------------------
+
+-- For a description of the laws, see e.g. Ross Paterson: Embedding a Class of
+-- Domain-Specific Languages in a Functional Language.
+-- Only a very rudimentary sanity check. Obviously not intended to "prove"
+-- this implementation indeed do respect the laws.
+
+laws_t0_lhs :: [Double]
+laws_t0_lhs = testSF1 (arr id >>> integral)
+laws_t0_rhs :: [Double]
+laws_t0_rhs = testSF1 (integral)
+
+laws_t1_lhs :: [Double]
+laws_t1_lhs = testSF1 (integral >>> arr id)
+laws_t1_rhs :: [Double]
+laws_t1_rhs = testSF1 (integral)
+
+laws_t2_lhs :: [Double]
+laws_t2_lhs = testSF1 ((integral >>> arr (*0.5)) >>> integral)
+laws_t2_rhs :: [Double]
+laws_t2_rhs = testSF1 (integral >>> (arr (*0.5) >>> integral))
+
+laws_t3_lhs :: [Double]
+laws_t3_lhs = testSF1 (arr ((*2.5) . (+3.0)))
+laws_t3_rhs :: [Double]
+laws_t3_rhs = testSF1 (arr (+3.0) >>> arr (*2.5))
+
+laws_t4_lhs :: [(Double, Double)]
+laws_t4_lhs = testSF1 (arr dup >>> first (arr (*2.5)))
+laws_t4_rhs :: [(Double, Double)]
+laws_t4_rhs = testSF1 (arr dup >>> arr ((*2.5) *** id))
+
+laws_t5_lhs :: [(Double, Double)]
+laws_t5_lhs = testSF1 (arr dup >>> (first (integral >>> arr (+3.0))))
+laws_t5_rhs :: [(Double, Double)]
+laws_t5_rhs = testSF1 (arr dup >>> (first integral >>> first (arr (+3.0))))
+
+laws_t6_lhs :: [(Double, Double)]
+laws_t6_lhs = testSF1 (arr dup >>> (first integral >>> arr (id *** (+3.0))))
+laws_t6_rhs :: [(Double, Double)]
+laws_t6_rhs = testSF1 (arr dup >>> (arr (id *** (+3.0)) >>> first integral))
+
+laws_t7_lhs :: [Double]
+laws_t7_lhs = testSF1 (arr dup >>> (first integral >>> arr fst))
+laws_t7_rhs :: [Double]
+laws_t7_rhs = testSF1 (arr dup >>> (arr fst >>> integral))
+
+laws_t8_lhs :: [(Double, (Double, ()))]
+laws_t8_lhs = testSF1 (arr (\x -> ((x,x),()))
+		       >>> (first (first integral) >>> arr assoc))
+laws_t8_rhs :: [(Double, (Double, ()))]
+laws_t8_rhs = testSF1 (arr (\x -> ((x,x),()))
+		       >>> (arr assoc >>> first integral))
+
+
+laws_trs =
+    [ laws_t0_lhs ~= laws_t0_rhs,
+      laws_t1_lhs ~= laws_t1_rhs,
+      laws_t2_lhs ~= laws_t2_rhs,
+      laws_t3_lhs ~= laws_t3_rhs,
+      laws_t4_lhs ~= laws_t4_rhs,
+      laws_t5_lhs ~= laws_t5_rhs,
+      laws_t6_lhs ~= laws_t6_rhs,
+      laws_t7_lhs ~= laws_t7_rhs,
+      laws_t8_lhs ~= laws_t8_rhs
+    ]
+
+laws_tr = and laws_trs
diff --git a/tests/TestsLoop.hs b/tests/TestsLoop.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsLoop.hs
@@ -0,0 +1,207 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsLoop.hs,v 1.6 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsLoop					                         *
+*       Purpose:        Test cases for loop				     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsLoop (loop_trs, loop_tr, loop_st0, loop_st0r,
+		      loop_st1, loop_st1r) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for loop
+------------------------------------------------------------------------------
+
+loop_acc :: SF (Double, Double) (Double, Double)
+loop_acc = arr (\(x, y)->(x+y, x+y))
+
+loop_t0 :: [Double]
+loop_t0 = testSF1 (loop (constant (42.0, 43.0)))
+loop_t0r =
+    [42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0,
+     42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0, 42.0,
+     42.0, 42.0, 42.0, 42.0, 42.0]
+
+loop_t1 :: [Double]
+loop_t1 = testSF1 (loop identity)
+loop_t1r =
+    [0.0,  1.0,  2.0,  3.0,  4.0,  5.0,  6.0,  7.0,  8.0,  9.0,
+     10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0,
+     20.0, 21.0, 22.0, 23.0, 24.0]
+
+loop_t2 :: [Time]
+loop_t2 = testSF1 (loop (first localTime))
+loop_t2r =
+    [0.0,  0.25, 0.5,  0.75, 1.0,
+     1.25, 1.5,  1.75, 2.0,  2.25,
+     2.5,  2.75, 3.0,  3.25, 3.5,
+     3.75, 4.0,  4.25, 4.5,  4.75,
+     5.0,  5.25, 5.5,  5.75, 6.0]
+
+-- AC, 10-March-2002: I think this is the simplest test that will
+-- fail with AltST.
+loop_t3 :: [Time]
+loop_t3 = testSF1 (loop (second (iPre 0)))
+loop_t3r =
+    [0.0,  1.0,  2.0,  3.0,  4.0,
+     5.0,  6.0,  7.0,  8.0,  9.0,
+     10.0, 11.0, 12.0, 13.0, 14.0,
+     15.0, 16.0, 17.0, 18.0, 19.0,
+     20.0, 21.0, 22.0, 23.0, 24.0]
+
+loop_t4 :: [Double]
+loop_t4 = testSF1 (loop (second (iPre 0) >>> loop_acc))
+loop_t4r =
+    [0.0,   1.0,   3.0,   6.0,   10.0,
+     15.0,  21.0,  28.0,  36.0,  45.0,
+     55.0,  66.0,  78.0,  91.0,  105.0,
+     120.0, 136.0, 153.0, 171.0, 190.0,
+     210.0, 231.0, 253.0, 276.0, 300.0]
+
+loop_t5 :: [Double]
+loop_t5 = testSF2 (loop (second (iPre 0) >>> loop_acc))
+loop_t5r =
+    [0.0,  0.0,  0.0,  0.0,  0.0,
+     1.0,  2.0,  3.0,  4.0,  5.0,
+     7.0,  9.0,  11.0, 13.0, 15.0,
+     18.0, 21.0, 24.0, 27.0, 30.0,
+     34.0, 38.0, 42.0, 46.0, 50.0]
+
+loop_t6 :: [Double]
+loop_t6 = testSF1 (loop (iPre (0,0) >>> first localTime >>> loop_acc))
+loop_t6r =
+    [0.0,   0.25,  0.75,  1.5,   2.5,
+     3.75,  5.25,  7.0,   9.0,   11.25,
+     13.75, 16.5,  19.5,  22.75, 26.25,
+     30.0,  34.0,  38.25, 42.75, 47.5,
+     52.5,  57.75, 63.25, 69.0,  75.0]
+
+loop_t7 :: [Double]
+loop_t7 = testSF1 (loop (loop_acc >>> second (iPre 0)))
+loop_t7r = loop_t4r
+
+loop_t8 :: [Double]
+loop_t8 = testSF2 (loop (loop_acc >>> second (iPre 0)))
+loop_t8r = loop_t5r
+
+loop_t9 :: [Double]
+loop_t9 = testSF1 (loop (first localTime >>> loop_acc >>> iPre (0,0)))
+loop_t9r =
+    [0.0,   0.0,   0.25,  0.75,  1.5,
+     2.5,   3.75,  5.25,  7.0,   9.0,
+     11.25, 13.75, 16.5,  19.5,  22.75,
+     26.25, 30.0,  34.0,  38.25, 42.75,
+     47.5,  52.5,  57.75, 63.25, 69.0]
+
+loop_t10 :: [Double]
+loop_t10 = testSF1 (loop (loop_acc >>> second (iPre 0) >>> identity))
+loop_t10r = loop_t4r
+
+loop_t11 :: [Double]
+loop_t11 = testSF2 (loop (loop_acc >>> second (iPre 0) >>> identity))
+loop_t11r = loop_t5r
+
+loop_t12 :: [Double]
+loop_t12 = testSF1 (loop (first localTime
+                          >>> loop_acc
+                          >>> iPre (0,0)
+                          >>> identity))
+loop_t12r = loop_t9r
+
+-- Computation of approximation to exp 0, exp 1, ..., exp 5 by integration.
+-- Values as given by using exp directly:
+-- 1.0, 2.71828, 7.38906, 20.0855, 54.5981, 148.413
+loop_t13 :: [Double]
+loop_t13 =
+    let
+	es = embed (loop (second integral >>> arr (\(_, x) -> (x + 1, x + 1))))
+                   (deltaEncode 0.001 (repeat ()))
+    in
+	[es!!0, es!!1000, es!!2000, es!!3000, es!!4000, es!!5000]
+loop_t13r = [1.0,2.71692, 7.38167, 20.05544, 54.48911, 148.04276]
+
+loop_t14 :: [Double]
+loop_t14 =
+    let
+	es = embed (loop (arr (\(_, x) -> (x + 1, x + 1)) >>> second integral))
+                   (deltaEncode 0.001 (repeat ()))
+    in
+	[es!!0, es!!1000, es!!2000, es!!3000, es!!4000, es!!5000]
+loop_t14r = loop_t13r
+
+loop_t15 :: [Double]
+loop_t15 =
+    let
+	es = embed (loop (arr (\(_, x) -> (x + 1, x + 1))
+                          >>> second integral
+			  >>> identity))
+                   (deltaEncode 0.001 (repeat ()))
+    in
+	[es!!0, es!!1000, es!!2000, es!!3000, es!!4000, es!!5000]
+loop_t15r = loop_t13r
+
+-- A generator for factorial:  The least-fixed point of this function is
+-- the factorial function.
+
+factGen f n = if (n==0) then 1 else n*f(n-1)
+
+-- Can we use loop to construct a fixed point?
+loop_t16 :: [Int]
+loop_t16 = testSF1 (loop $ arr (\ (_,f) -> (f 4,factGen f)))
+loop_t16r =
+  [24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24]
+
+-- A simple loop test taken from MiniYampa:
+-- This results in pulling on the fed-back output during evaluation, because
+-- switch is strict in its input sample:
+loop_t17 :: [Double]
+loop_t17 = testSF1 (loop $ second $ (switch identity (const (arr fst))) >>> arr (\x -> (x,noEvent)) >>> (iPre (25, noEvent)))
+loop_t17r =
+  [0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,15.0,
+   16.0,17.0,18.0,19.0,20.0,21.0,22.0,23.0,24.0]
+
+loop_trs =
+    [ loop_t0  ~= loop_t0r,
+      loop_t1  ~= loop_t1r,
+      loop_t2  ~= loop_t2r,
+      loop_t3  ~= loop_t3r,
+      loop_t4  ~= loop_t4r,
+      loop_t5  ~= loop_t5r,
+      loop_t6  ~= loop_t6r,
+      loop_t7  ~= loop_t7r,
+      loop_t8  ~= loop_t8r,
+      loop_t9  ~= loop_t9r,
+      loop_t10 ~= loop_t10r,
+      loop_t11 ~= loop_t11r,
+      loop_t12 ~= loop_t12r,
+      loop_t13 ~= loop_t13r,
+      loop_t14 ~= loop_t14r,
+      loop_t15 ~= loop_t15r,
+      loop_t16 ~= loop_t16r,
+      loop_t17 ~= loop_t17r
+    ]
+
+loop_tr = and loop_trs
+
+loop_st0 = testSFSpaceLeak 2000000
+			   (loop (second (iPre 0) >>> loop_acc))
+loop_st0r = 9.999995e11
+
+-- A simple loop test taken from MiniYampa:
+-- This results in pulling on the fed-back output during evaluation, because
+-- switch is strict in its input sample:
+loop_st1 :: Double
+loop_st1 = testSFSpaceLeak 2000000
+             (loop $ second $ (switch identity (const (arr fst))) >>> arr (\x -> (x + x + x + x + x + x + x,noEvent)) >>> (iPre (25, noEvent)))
+loop_st1r = 999999.5
diff --git a/tests/TestsLoopIntegral.hs b/tests/TestsLoopIntegral.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsLoopIntegral.hs
@@ -0,0 +1,105 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsLoopIntegral.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  A F R P                                   *
+*                                                                            *
+*       Module:         TestsLoopIntegral				                     *
+*       Purpose:        Test cases for loopIntegral			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsLoopIntegral (loopIntegral_tr, loopIntegral_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for loopIntegral
+------------------------------------------------------------------------------
+
+-- Computation of approximation to exp 0, exp 1, ..., exp 5 by integration.
+-- Values as given by using exp directly:
+-- 1.0, 2.71828, 7.38906, 20.0855, 54.5981, 148.413
+loopIntegral_t0 =
+    let
+	es = embed (loopIntegral (arr (\(_, x) -> (x + 1, x + 1))))
+                   (deltaEncode 0.001 (repeat ()))
+    in
+	[es!!0, es!!1000, es!!2000, es!!3000, es!!4000, es!!5000]
+loopIntegral_t0r :: [Double]
+loopIntegral_t0r = [1.0,2.71692,7.38167,20.05544,54.48911,148.04276]
+
+
+-- Test case with a time varying signal transformer inside the loop.
+-- Starting at position 0 [m], accelerate by 1.0 [m/s^2] until position
+-- exceeds 2.0 [m]. Then accelerate by -1.0 [m/s^2] until position gets
+-- below 0.0 [m]. Then accelerate at 1.0 [m/s^2] again. And so on.
+
+type Position = Double
+type Velocity = Double
+type Acceleration = Double
+
+posCntrl :: SF b Position
+posCntrl = loopIntegral posCntrlNR
+    where
+	posCntrlNR :: SF (b, Velocity) (Position, Acceleration)
+	posCntrlNR =
+	    arr snd			-- Get the velocity.
+	    >>> integral		-- This integral gives us the position.
+	    >>> arr (\x -> (x,x))
+	    >>>
+		(second $
+		    arr (\x -> (x,x))
+		    >>>
+			(first $
+			    arr (>=2.0)
+			    >>> edge
+			    >>> (arr (fmap (const (constant (-1.0))))))
+		    >>>
+			(second $
+			    arr (< 0.0)
+			    >>> edge
+			    >>> (arr (fmap (const (constant 1.0)))))
+		    >>> arr (\(e1,e2) -> e1 `lMerge` e2)
+		    >>> arr (\e -> ((), e))
+		    >>> rSwitch (constant 1.0))
+
+
+loopIntegral_t1 = take 250 (embed posCntrl (deltaEncode 0.1 (repeat ())))
+
+-- Result only partially verified. But the sign of the acceleration changes
+-- at roughly the right points.
+loopIntegral_t1r :: [Double]
+loopIntegral_t1r =
+    [0.0,0.0,0.01,0.03,0.06,0.1,0.15,0.21,0.28,0.36,0.45,0.55,0.66,0.78,0.91,
+     1.05,1.2,1.36,1.53,1.71,1.9,2.1,2.31,2.51,2.7,2.88,3.05,3.21,3.36,3.5,
+     3.63,3.75,3.86,3.96,4.05,4.13,4.2,4.26,4.31,4.35,4.38,4.4,4.41,4.41,4.4,
+     4.38,4.35,4.31,4.26,4.2,4.13,4.05,3.96,3.86,3.75,3.63,3.5,3.36,3.21,3.05,
+     2.88,2.7,2.51,2.31,2.1,1.88,1.65,1.41,1.16,0.9,0.63,0.35,0.06,-0.24,
+     -0.55,-0.85,-1.14,-1.42,-1.69,-1.95,-2.2,-2.44,-2.67,-2.89,-3.1,-3.3,
+     -3.49,-3.67,-3.84,-4.0,-4.15,-4.29,-4.42,-4.54,-4.65,-4.75,-4.84,-4.92,
+     -4.99,-5.05,-5.1,-5.14,-5.17,-5.19,-5.2,-5.2,-5.19,-5.17,-5.14,-5.1,
+     -5.05,-4.99,-4.92,-4.84,-4.75,-4.65,-4.54,-4.42,-4.29,-4.15,-4.0,-3.84,
+     -3.67,-3.49,-3.3,-3.1,-2.89,-2.67,-2.44,-2.2,-1.95,-1.69,-1.42,-1.14,
+     -0.85,-0.55,-0.24,0.08,0.41,0.75,1.1,1.46,1.83,2.21,2.6,2.98,3.35,3.71,
+     4.06,4.4,4.73,5.05,5.36,5.66,5.95,6.23,6.5,6.76,7.01,7.25,7.48,7.7,7.91,
+     8.11,8.3,8.48,8.65,8.81,8.96,9.1,9.23,9.35,9.46,9.56,9.65,9.73,9.8,9.86,
+     9.91,9.95,9.98,10.0,10.01,10.01,10.0,9.98,9.95,9.91,9.86,9.8,9.73,9.65,
+     9.56,9.46,9.35,9.23,9.1,8.96,8.81,8.65,8.48,8.3,8.11,7.91,7.7,7.48,7.25,
+     7.01,6.76,6.5,6.23,5.95,5.66,5.36,5.05,4.73,4.4,4.06,3.71,3.35,2.98,2.6,
+     2.21,1.81,1.4,0.98,0.55,0.11,-0.34,-0.80,-1.25,-1.69,-2.12,-2.54,-2.95,
+     -3.35,-3.74,-4.12,-4.49,-4.85,-5.2,-5.54,-5.87,-6.19,-6.5,-6.8,-7.09,
+     -7.37,-7.64,-7.9]
+
+
+loopIntegral_trs =
+    [ loopIntegral_t0 ~= loopIntegral_t0r,
+      loopIntegral_t1 ~= loopIntegral_t1r
+    ]
+
+loopIntegral_tr = and loopIntegral_trs
diff --git a/tests/TestsLoopLaws.hs b/tests/TestsLoopLaws.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsLoopLaws.hs
@@ -0,0 +1,110 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsLoopLaws.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsLoopLaws                                        *
+*       Purpose:        Test cases based on the arrow laws for loop	     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsLoopLaws (looplaws_trs, looplaws_tr) where
+
+import Data.Tuple(swap)
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases based on the arrow laws for loop
+------------------------------------------------------------------------------
+
+-- For a description of the laws, see Ross Paterson: Embedding a Class of
+-- Domain-Specific Languages in a Functional Language.
+-- Only a very rudimentary sanity check. Obviously not intended to "prove"
+-- this implementation indeed do respect the laws.
+
+simple_loop :: ((a,c) -> (b,c)) -> (a -> b)
+simple_loop f a = b
+    where
+	(b, c) = f (a, c)
+
+
+-- Left tightening
+looplaws_t0_f = second integral >>> arr swap
+looplaws_t0_h :: Fractional a => SF a a
+looplaws_t0_h = arr (+10.0)
+looplaws_t0_lhs :: [Double]
+looplaws_t0_lhs = testSF1 (loop (first looplaws_t0_h >>> looplaws_t0_f))
+looplaws_t0_rhs :: [Double]
+looplaws_t0_rhs = testSF1 (looplaws_t0_h >>> loop looplaws_t0_f)
+
+
+-- Right tightening
+looplaws_t1_f = second integral >>> arr swap
+looplaws_t1_h :: Fractional a => SF a a
+looplaws_t1_h = arr (+10.0)
+looplaws_t1_lhs :: [Double]
+looplaws_t1_lhs = testSF1 (loop (looplaws_t1_f >>> first looplaws_t1_h))
+looplaws_t1_rhs :: [Double]
+looplaws_t1_rhs = testSF1 (loop looplaws_t1_f >>> looplaws_t1_h)
+
+
+-- Sliding
+-- Used to work with only signature t2_f :: Fractional a -> SF a a
+looplaws_t2_f :: SF (Double, Double) (Double, Double)
+looplaws_t2_f = integral
+looplaws_t2_k = id *** (+42.0)
+looplaws_t2_lhs :: [Double]
+looplaws_t2_lhs = testSF1 (loop (looplaws_t2_f >>> arr looplaws_t2_k))
+looplaws_t2_rhs :: [Double]
+looplaws_t2_rhs = testSF1 (loop (arr looplaws_t2_k >>> looplaws_t2_f))
+
+
+-- Vanishing
+-- The lazy pattern matching (~) is necessary to avoid a black hole in the
+-- RHS due to premature forcing of tuples. As far as I can tell, loop is
+-- as lazy as it can be, and this problem could not have been solved by
+-- "fixing" the loop definition.
+looplaws_t3_f = second integral
+		>>> first (arr swap)
+		>>> arr (\ ~((a,b),c) -> ((a,c),b))
+looplaws_t3_lhs :: [Double]
+looplaws_t3_lhs = testSF1 (loop (loop looplaws_t3_f))
+looplaws_t3_rhs :: [Double]
+looplaws_t3_rhs = testSF1 (loop (arr assocInv >>> looplaws_t3_f >>> arr assoc))
+
+
+-- Superposing
+looplaws_t4_f = second integral >>> arr swap
+looplaws_t4_lhs :: [(Double,Double)]
+looplaws_t4_lhs = testSF1 (arr dup >>> (second (loop looplaws_t4_f)))
+looplaws_t4_rhs :: [(Double, Double)]
+looplaws_t4_rhs = testSF1 (arr dup >>> (loop (arr assoc
+				        >>> second looplaws_t4_f
+				        >>> arr assocInv)))
+
+
+-- Extension
+looplaws_t5_f = \(a,c) -> (take 5 c, a : c)
+looplaws_t5_lhs :: [[Double]]
+looplaws_t5_lhs = testSF1 (loop (arr looplaws_t5_f))
+looplaws_t5_rhs :: [[Double]]
+looplaws_t5_rhs = testSF1 (arr (simple_loop looplaws_t5_f))
+
+
+looplaws_trs =
+    [ looplaws_t0_lhs  ~= looplaws_t0_rhs,
+      looplaws_t1_lhs  ~= looplaws_t1_rhs,
+      looplaws_t2_lhs  ~= looplaws_t2_rhs,
+      looplaws_t3_lhs  ~= looplaws_t3_rhs,
+      looplaws_t4_lhs  ~= looplaws_t4_rhs,
+      looplaws_t5_lhs  ~= looplaws_t5_rhs
+    ]
+
+looplaws_tr = and looplaws_trs
diff --git a/tests/TestsLoopPre.hs b/tests/TestsLoopPre.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsLoopPre.hs
@@ -0,0 +1,63 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsLoopPre.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsLoopPre				                         *
+*       Purpose:        Test cases for loopPre				     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsLoopPre (loopPre_tr, loopPre_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for loopPre
+------------------------------------------------------------------------------
+
+loop_acc :: SF (Double, Double) (Double, Double)
+loop_acc = arr (\(x, y)->(x+y, x+y))
+
+-- This kind of test will fail for infinitesimal delay!
+loopPre_t0 = testSF1 (loopPre 0 loop_acc)
+loopPre_t0r =
+    [0.0,1.0,3.0,6.0,10.0,15.0,21.0,28.0,36.0,45.0,55.0,66.0,78.0,91.0,
+     105.0,120.0,136.0,153.0,171.0,190.0,210.0,231.0,253.0,276.0,300.0]
+
+loopPre_t1 = testSF2 (loopPre 0 loop_acc)
+loopPre_t1r =
+    [0.0,0.0,0.0,0.0,0.0,1.0,2.0,3.0,4.0,5.0,7.0,9.0,11.0,13.0,15.0,18.0,
+     21.0,24.0,27.0,30.0,34.0,38.0,42.0,46.0,50.0]
+
+-- This kind of test will fail for infinitesimal delay!
+loopPre_t2 = testSF1 (loopPre False (arr (dup . not . snd)))
+loopPre_t2r =
+    [True,False,True,False,True,False,True,False,True,False,True,False,
+     True,False,True,False,True,False,True,False,True,False,True,False,True]
+
+loopPre_t3 = testSF1 (loopPre 0 (first localTime))
+loopPre_t3r =
+    [0.0,0.25,0.5,0.75,1.0,1.25,1.5,1.75,2.0,2.25,2.5,2.75,3.0,3.25,3.5,3.75,
+     4.0,4.25,4.5,4.75,5.0,5.25,5.5,5.75,6.0]
+
+loopPre_t4 = testSF1 (loopPre 0 (first localTime >>> loop_acc))
+loopPre_t4r =
+    [0.0,0.25,0.75,1.5,2.5,3.75,5.25,7.0,9.0,11.25,13.75,16.5,19.5,22.75,
+     26.25,30.0,34.0,38.25,42.75,47.5,52.5,57.75,63.25,69.0,75.0]
+
+loopPre_trs =
+    [ loopPre_t0 ~= loopPre_t0r,
+      loopPre_t1 ~= loopPre_t1r,
+      loopPre_t2 ~= loopPre_t2r,
+      loopPre_t3 ~= loopPre_t3r,
+      loopPre_t4 ~= loopPre_t4r
+    ]
+
+loopPre_tr = and loopPre_trs
diff --git a/tests/TestsPSwitch.hs b/tests/TestsPSwitch.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsPSwitch.hs
@@ -0,0 +1,325 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsPSwitch.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsPSwitch				                         *
+*       Purpose:        Test cases for pSwitchB and dpSwitchB		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsPSwitch (
+    pswitch_tr,
+    pswitch_trs,
+    pswitch_st0,
+    pswitch_st0r,
+    pswitch_st1,
+    pswitch_st1r
+) where
+
+import Data.List (findIndex)
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for pSwitchB and dpSwitchB
+------------------------------------------------------------------------------
+
+pswitch_inp1 = deltaEncode 0.1 [0.0, 0.5 ..]
+
+whenFstGE :: Ord a => a -> c -> SF (a, b) (Event c)
+whenFstGE a c = arr fst >>> arr (>= a) >>> edge >>> arr (`tag` c)
+
+pswitch_t0 :: [[Double]]
+pswitch_t0 = take 20 $ embed sf pswitch_inp1
+    where
+	sf =
+	    pSwitchB [] (whenFstGE 1.25 10.0) $ \sfs x ->
+	    pSwitchB (integral:sfs) (whenFstGE 3.75 10.0) $ \sfs x ->
+	    pSwitchB ((integral>>>arr(+x)):sfs)(whenFstGE 5.25 20.0) $ \sfs x->
+	    pSwitchB ((integral>>>arr(+x)):sfs)(whenFstGE 7.25 20.0) $ \sfs _->
+	    parB (take 2 sfs)
+
+pswitch_t0r =
+    [[],			-- 0.0
+     [],			-- 0.5
+     [],			-- 1.0
+     [0.0],			-- 1.5
+     [0.15],			-- 2.0
+     [0.35],			-- 2.5
+     [0.60],			-- 3.0
+     [0.90],			-- 3.5
+     [10.00, 1.25],		-- 4.0
+     [10.40, 1.65],		-- 4.5
+     [10.85, 2.10],		-- 5.0
+     [20.00, 11.35, 2.60],	-- 5.5
+     [20.55, 11.90, 3.15],	-- 6.0
+     [21.15, 12.50, 3.75],	-- 6.5
+     [21.80, 13.15, 4.40],	-- 7.0
+     [22.50, 13.85],		-- 7.5
+     [23.25, 14.60],		-- 8.0
+     [24.05, 15.40],		-- 8.5
+     [24.90, 16.25],		-- 9.0
+     [25.80, 17.15]]		-- 9.5
+
+
+pswitch_t1 :: [[Double]]
+pswitch_t1 = take 20 $ embed sf pswitch_inp1
+    where
+	sf =
+	    dpSwitchB [] (whenFstGE 1.25 10.0) $ \sfs x ->
+	    dpSwitchB (integral:sfs) (whenFstGE 3.75 10.0) $ \sfs x ->
+	    dpSwitchB ((integral>>>arr(+x)):sfs)(whenFstGE 5.25 20.0)$ \sfs x->
+	    dpSwitchB ((integral>>>arr(+x)):sfs)(whenFstGE 7.25 20.0)$ \sfs _->
+	    parB (take 2 sfs)
+
+
+pswitch_t1r =
+    [[],			-- 0.0
+     [],			-- 0.5
+     [],			-- 1.0
+     [],			-- 1.5
+     [0.15],			-- 2.0
+     [0.35],			-- 2.5
+     [0.60],			-- 3.0
+     [0.90],			-- 3.5
+     [1.25],			-- 4.0
+     [10.40, 1.65],		-- 4.5
+     [10.85, 2.10],		-- 5.0
+     [11.35, 2.60],		-- 5.5
+     [20.55, 11.90, 3.15],	-- 6.0
+     [21.15, 12.50, 3.75],	-- 6.5
+     [21.80, 13.15, 4.40],	-- 7.0
+     [22.50, 13.85, 5.10],	-- 7.5
+     [23.25, 14.60],		-- 8.0
+     [24.05, 15.40],		-- 8.5
+     [24.90, 16.25],		-- 9.0
+     [25.80, 17.15]]		-- 9.5
+
+
+pswitch_t2 :: [[Double]]
+pswitch_t2 = take 20 $ embed sf pswitch_inp1
+    where
+	sf =
+	    pSwitchB [] (now 10.0) $ \sfs x ->
+	    pSwitchB (integral:sfs) (whenFstGE 3.75 10.0) $ \sfs x ->
+	    pSwitchB ((integral>>>arr(+x)):sfs)(whenFstGE 5.25 20.0) $ \sfs x->
+	    pSwitchB ((integral>>>arr(+x)):sfs)(now 20.0) $ \sfs _->
+	    parB (take 2 sfs)
+
+pswitch_t2r =
+    [[0.00],		-- 0.0
+     [0.00],		-- 0.5
+     [0.05],		-- 1.0
+     [0.15],		-- 1.5
+     [0.30],		-- 2.0
+     [0.50],		-- 2.5
+     [0.75],		-- 3.0
+     [1.05],		-- 3.5
+     [10.00,  1.40],	-- 4.0
+     [10.40,  1.80],	-- 4.5
+     [10.85,  2.25],	-- 5.0
+     [20.00, 11.35],	-- 5.5
+     [20.55, 11.90],	-- 6.0
+     [21.15, 12.50],	-- 6.5
+     [21.80, 13.15],	-- 7.0
+     [22.50, 13.85],	-- 7.5
+     [23.25, 14.60],	-- 8.0
+     [24.05, 15.40],	-- 8.5
+     [24.90, 16.25],	-- 9.0
+     [25.80, 17.15]]	-- 9.5
+
+
+pswitch_t3 :: [[Double]]
+pswitch_t3 = take 20 $ embed sf pswitch_inp1
+    where
+	sf =
+	    dpSwitchB [] (now 10.0) $ \sfs x ->
+	    dpSwitchB (integral:sfs) (whenFstGE 3.75 10.0) $ \sfs x ->
+	    dpSwitchB ((integral>>>arr(+x)):sfs)(whenFstGE 5.25 20.0)$ \sfs x->
+	    dpSwitchB ((integral>>>arr(+x)):sfs) (now 20.0) $ \sfs _->
+	    parB (take 2 sfs)
+
+pswitch_t3r =
+    [[],		-- 0.0
+     [0.00],		-- 0.5
+     [0.05],		-- 1.0
+     [0.15],		-- 1.5
+     [0.30],		-- 2.0
+     [0.50],		-- 2.5
+     [0.75],		-- 3.0
+     [1.05],		-- 3.5
+     [1.40],		-- 4.0
+     [10.40,  1.80],	-- 4.5
+     [10.85,  2.25],	-- 5.0
+     [11.35,  2.75],	-- 5.5
+     [20.55, 11.90],	-- 6.0
+     [21.15, 12.50],	-- 6.5
+     [21.80, 13.15],	-- 7.0
+     [22.50, 13.85],	-- 7.5
+     [23.25, 14.60],	-- 8.0
+     [24.05, 15.40],	-- 8.5
+     [24.90, 16.25],	-- 9.0
+     [25.80, 17.15]]	-- 9.5
+
+
+-- Starts three "ramps" with different phase. As soon as one exceeds a
+-- threshold, it's restarted, while the others are left alone. The
+-- observaton of the output is done via the loop (rather than the directly
+-- from the outputs of the signal functions in the collection), thus the
+-- use of a delayed switch is essential.
+
+pswitch_ramp :: Double -> SF a Double
+pswitch_ramp phase = constant 2.0 >>> integral >>> arr (+phase)
+
+-- We assume that only one signal function will reach the limit at a time.
+pswitch_limit :: Double -> SF ((a, [Double]), b) (Event Int)
+pswitch_limit x = arr (snd . fst) >>> arr (findIndex (>=x)) >>> edgeJust
+
+pswitch_t4 :: [[Double]]
+pswitch_t4 = take 30 $ embed (loop sf) (deltaEncode 0.1 (repeat ()))
+    where
+        sf :: SF (a, [Double]) ([Double],[Double])
+	sf = dpSwitchB [pswitch_ramp 0.0, pswitch_ramp 1.0, pswitch_ramp 2.0]
+        	       (pswitch_limit 2.99)
+		       pswitch_t4rec
+	     >>> arr dup
+
+pswitch_t4rec :: [SF (a, [Double]) Double]
+                 -> Int
+                 -> SF (a, [Double]) [Double]
+pswitch_t4rec sfs n =
+    dpSwitchB (take n sfs ++ [pswitch_ramp 0.0] ++ drop (n+1) sfs)
+	      (pswitch_limit 2.99)
+	      pswitch_t4rec
+
+pswitch_t4r =
+    [[0.0, 1.0, 2.0],
+     [0.2, 1.2, 2.2],
+     [0.4, 1.4, 2.4],
+     [0.6, 1.6, 2.6],
+     [0.8, 1.8, 2.8],
+     [1.0, 2.0, 3.0],
+     [1.2, 2.2, 0.2],
+     [1.4, 2.4, 0.4],
+     [1.6, 2.6, 0.6],
+     [1.8, 2.8, 0.8],
+     [2.0, 3.0, 1.0],
+     [2.2, 0.2, 1.2],
+     [2.4, 0.4, 1.4],
+     [2.6, 0.6, 1.6],
+     [2.8, 0.8, 1.8],
+     [3.0, 1.0, 2.0],
+     [0.2, 1.2, 2.2],
+     [0.4, 1.4, 2.4],
+     [0.6, 1.6, 2.6],
+     [0.8, 1.8, 2.8],
+     [1.0, 2.0, 3.0],
+     [1.2, 2.2, 0.2],
+     [1.4, 2.4, 0.4],
+     [1.6, 2.6, 0.6],
+     [1.8, 2.8, 0.8],
+     [2.0, 3.0, 1.0],
+     [2.2, 0.2, 1.2],
+     [2.4, 0.4, 1.4],
+     [2.6, 0.6, 1.6],
+     [2.8, 0.8, 1.8]]
+
+
+-- Variation of the test above, with direct observation (not via loop) and
+-- immediate switch.
+
+-- We assume that only one signal function will reach the limit at a time.
+pswitch_limit2 :: Double -> SF (a, [Double]) (Event Int)
+pswitch_limit2 x = arr snd >>> arr (findIndex (>=x)) >>> edgeJust
+
+pswitch_t5 :: [([Double], Double)]
+pswitch_t5 = take 30 $ embed (loop sf) (deltaEncode 0.1 (repeat ()))
+    where
+        sf :: SF (a, [Double]) (([Double], Double), [Double])
+	sf = ((pSwitchB [pswitch_ramp 0.0, pswitch_ramp 1.0, pswitch_ramp 2.0]
+        	        (pswitch_limit2 2.99)
+		        pswitch_t5rec)
+	      &&& (arr snd >>> arr sum))
+	     >>> arr (\(xs, y) -> ((xs, y), xs))
+
+pswitch_t5rec :: [SF (a, [Double]) Double]
+                 -> Int
+                 -> SF (a, [Double]) [Double]
+pswitch_t5rec sfs n =
+    pSwitchB (take n sfs ++ [pswitch_ramp 0.0] ++ drop (n+1) sfs)
+	     (pswitch_limit2 2.99)
+	     pswitch_t5rec
+
+pswitch_t5r =
+    [([0.0, 1.0, 2.0], 3.0),
+     ([0.2, 1.2, 2.2], 3.6),
+     ([0.4, 1.4, 2.4], 4.2),
+     ([0.6, 1.6, 2.6], 4.8),
+     ([0.8, 1.8, 2.8], 5.4),
+     ([1.0, 2.0, 0.0], 3.0),
+     ([1.2, 2.2, 0.2], 3.6),
+     ([1.4, 2.4, 0.4], 4.2),
+     ([1.6, 2.6, 0.6], 4.8),
+     ([1.8, 2.8, 0.8], 5.4),
+     ([2.0, 0.0, 1.0], 3.0),
+     ([2.2, 0.2, 1.2], 3.6),
+     ([2.4, 0.4, 1.4], 4.2),
+     ([2.6, 0.6, 1.6], 4.8),
+     ([2.8, 0.8, 1.8], 5.4),
+     ([0.0, 1.0, 2.0], 3.0),
+     ([0.2, 1.2, 2.2], 3.6),
+     ([0.4, 1.4, 2.4], 4.2),
+     ([0.6, 1.6, 2.6], 4.8),
+     ([0.8, 1.8, 2.8], 5.4),
+     ([1.0, 2.0, 0.0], 3.0),
+     ([1.2, 2.2, 0.2], 3.6),
+     ([1.4, 2.4, 0.4], 4.2),
+     ([1.6, 2.6, 0.6], 4.8),
+     ([1.8, 2.8, 0.8], 5.4),
+     ([2.0, 0.0, 1.0], 3.0),
+     ([2.2, 0.2, 1.2], 3.6),
+     ([2.4, 0.4, 1.4], 4.2),
+     ([2.6, 0.6, 1.6], 4.8),
+     ([2.8, 0.8, 1.8], 5.4)]
+
+
+pswitch_trs =
+    [ pswitch_t0 ~= pswitch_t0r,
+      pswitch_t1 ~= pswitch_t1r,
+      pswitch_t2 ~= pswitch_t2r,
+      pswitch_t3 ~= pswitch_t3r,
+      pswitch_t4 ~= pswitch_t4r,
+      pswitch_t5 ~= pswitch_t5r
+    ]
+
+pswitch_tr = and pswitch_trs
+
+
+pswitch_st0 = testSFSpaceLeak 1000000 (loop sf)
+    where
+        sf :: SF (a, [Double]) ([Double],[Double])
+	sf = dpSwitchB [pswitch_ramp 0.0, pswitch_ramp 1.0, pswitch_ramp 2.0]
+        	       (pswitch_limit 2.99)
+		       pswitch_t4rec
+	     >>> arr dup
+
+pswitch_st0r = [1.5,2.5,0.5]
+
+
+pswitch_st1 = testSFSpaceLeak 1000000 (loop sf)
+    where
+        sf :: SF (a, [Double]) (([Double], Double), [Double])
+	sf = ((pSwitchB [pswitch_ramp 0.0, pswitch_ramp 1.0, pswitch_ramp 2.0]
+        	        (pswitch_limit2 2.99)
+		        pswitch_t5rec)
+	      &&& (arr snd >>> arr sum))
+	     >>> arr (\(xs, y) -> ((xs, y), xs))
+
+pswitch_st1r = ([1.5,2.5,0.5],4.5)
diff --git a/tests/TestsPre.hs b/tests/TestsPre.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsPre.hs
@@ -0,0 +1,209 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsDelay.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsPre					                         *
+*       Purpose:        Test cases for pre and (derived) combinators	     *
+*			that (semantically) involves a pre.		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*             Copyright (c) University of Nottingham, 2005                   *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsPre (pre_tr, pre_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for pre and related combinators
+------------------------------------------------------------------------------
+
+pre_t0 = testSF1 (iPre 17)
+pre_t0r =
+    [17.0,0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,
+     15.0,16.0,17.0,18.0,19.0,20.0,21.0,22.0,23.0]
+
+pre_t1 = testSF2 (iPre 17)
+pre_t1r =
+    [17.0,0.0,0.0,0.0,0.0,0.0,1.0,1.0,1.0,1.0,1.0,2.0,2.0,2.0,2.0,2.0,
+     3.0,3.0,3.0,3.0,3.0,4.0,4.0,4.0,4.0]
+
+pre_t2 = testSF1 (time
+                  >>> arr (\t -> sin (0.5 * t * pi + pi))
+                  >>> loop (arr (\(x1,x2) -> let x' = max x1 x2 in (x',x'))
+                            >>> second (iPre 0.0)))
+
+pre_t2r =
+    take 25
+         (let xs = [ sin (0.5 * t * pi + pi) | t <- [0.0, 0.25 ..] ]
+          in tail (scanl max 0 xs))
+
+
+-- This is a (somewhat strange) way of doing a counter that
+-- stops after reaching a threshold. Note that the ingoing event
+-- is *control dependent* on the output of the counter, so
+-- "dHold" really has to have the capability of delivering an
+-- output without looking at the current input at all.
+pre_t3, pre_t3r :: [Int]
+pre_t3 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = repeatedly 1.0 ()
+             >>> (loop $
+                      arr (\(e,c) -> (e `tag` (c + 1)) `gate` (c < 10))
+                      >>> dHold 0
+                      >>> arr dup)
+pre_t3r = [0,0,0,0,	-- 0s
+           0,1,1,1,	-- 1s
+           1,2,2,2,	-- 2s
+           2,3,3,3,	-- 3s
+           3,4,4,4,	-- 4s
+           4,5,5,5,	-- 5s
+           5,6,6,6,	-- 6s
+           6,7,7,7,	-- 7s
+           7,8,8,8,	-- 8s
+           8,9,9,9,	-- 9s
+           9,10,10,10,	-- 10s
+           10,10,10,10,	-- 11s
+           10,10]	-- 12s
+
+-- Version of the above that tests that thigs still work OK also if
+-- there is an initial event.
+pre_t4, pre_t4r :: [Int]
+pre_t4 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = (now () &&& repeatedly 1.0 ()) >>> arr (uncurry lMerge)
+             >>> (loop $
+                      arr (\(e,c) -> (e `tag` (c + 1)) `gate` (c < 10))
+                      >>> dHold 0
+                      >>> arr dup)
+pre_t4r = [0,1,1,1,	-- 0s
+           1,2,2,2,	-- 1s
+           2,3,3,3,	-- 2s
+           3,4,4,4,	-- 3s
+           4,5,5,5,	-- 4s
+           5,6,6,6,	-- 5s
+           6,7,7,7,	-- 6s
+           7,8,8,8,	-- 7s
+           8,9,9,9,	-- 8s
+           9,10,10,10,	-- 9s
+           10,10,10,10,	-- 10s
+           10,10,10,10,	-- 11s
+           10,10]	-- 12s
+
+
+-- Similar test to "pre_t3" above but for dAccumHold.
+pre_t5, pre_t5r :: [Int]
+pre_t5 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = repeatedly 1.0 ()
+             >>> (loop $
+                      arr (\(e,c) -> (e `tag` (+1)) `gate` (c < 10))
+                      >>> dAccumHold 0
+                      >>> arr dup)
+pre_t5r = [0,0,0,0,	-- 0s
+           0,1,1,1,	-- 1s
+           1,2,2,2,	-- 2s
+           2,3,3,3,	-- 3s
+           3,4,4,4,	-- 4s
+           4,5,5,5,	-- 5s
+           5,6,6,6,	-- 6s
+           6,7,7,7,	-- 7s
+           7,8,8,8,	-- 8s
+           8,9,9,9,	-- 9s
+           9,10,10,10,	-- 10s
+           10,10,10,10,	-- 11s
+           10,10]	-- 12s
+
+
+-- Similar test to "pre_t4" above but for dAccumHold.
+pre_t6, pre_t6r :: [Int]
+pre_t6 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = (now () &&& repeatedly 1.0 ()) >>> arr (uncurry lMerge)
+             >>> (loop $
+                      arr (\(e,c) -> (e `tag` (+1)) `gate` (c < 10))
+                      >>> dAccumHold 0
+                      >>> arr dup)
+pre_t6r = [0,1,1,1,	-- 0s
+           1,2,2,2,	-- 1s
+           2,3,3,3,	-- 2s
+           3,4,4,4,	-- 3s
+           4,5,5,5,	-- 4s
+           5,6,6,6,	-- 5s
+           6,7,7,7,	-- 6s
+           7,8,8,8,	-- 7s
+           8,9,9,9,	-- 8s
+           9,10,10,10,	-- 9s
+           10,10,10,10,	-- 10s
+           10,10,10,10,	-- 11s
+           10,10]	-- 12s
+
+
+-- Similar test to "pre_t3" above but for dAccumHoldBy.
+pre_t7, pre_t7r :: [Int]
+pre_t7 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = repeatedly 1.0 ()
+             >>> (loop $
+                      arr (\(e,c) -> e `gate` (c < 10))
+                      >>> dAccumHoldBy (\c _ -> c + 1) 0
+                      >>> arr dup)
+pre_t7r = [0,0,0,0,	-- 0s
+           0,1,1,1,	-- 1s
+           1,2,2,2,	-- 2s
+           2,3,3,3,	-- 3s
+           3,4,4,4,	-- 4s
+           4,5,5,5,	-- 5s
+           5,6,6,6,	-- 6s
+           6,7,7,7,	-- 7s
+           7,8,8,8,	-- 8s
+           8,9,9,9,	-- 9s
+           9,10,10,10,	-- 10s
+           10,10,10,10,	-- 11s
+           10,10]	-- 12s
+
+
+-- Similar test to "pre_t4" above but for dAccumHoldBy.
+pre_t8, pre_t8r :: [Int]
+pre_t8 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = (now () &&& repeatedly 1.0 ()) >>> arr (uncurry lMerge)
+             >>> (loop $
+                      arr (\(e,c) -> e `gate` (c < 10))
+                      >>> dAccumHoldBy (\c _ -> c + 1) 0
+                      >>> arr dup)
+pre_t8r = [0,1,1,1,	-- 0s
+           1,2,2,2,	-- 1s
+           2,3,3,3,	-- 2s
+           3,4,4,4,	-- 3s
+           4,5,5,5,	-- 4s
+           5,6,6,6,	-- 5s
+           6,7,7,7,	-- 6s
+           7,8,8,8,	-- 7s
+           8,9,9,9,	-- 8s
+           9,10,10,10,	-- 9s
+           10,10,10,10,	-- 10s
+           10,10,10,10,	-- 11s
+           10,10]	-- 12s
+
+
+
+pre_trs =
+    [ pre_t0 ~= pre_t0r,
+      pre_t1 ~= pre_t1r,
+      pre_t2 ~= pre_t2r,
+      pre_t3 == pre_t3r,
+      pre_t4 == pre_t4r,
+      pre_t5 == pre_t5r,
+      pre_t6 == pre_t6r,
+      pre_t7 == pre_t7r,
+      pre_t8 == pre_t8r
+    ]
+
+pre_tr = and pre_trs
diff --git a/tests/TestsRPSwitch.hs b/tests/TestsRPSwitch.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsRPSwitch.hs
@@ -0,0 +1,246 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsRPSwitch.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsRPSwitch				                         *
+*       Purpose:        Test cases for rpSwitchB and drpSwitchB		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsRPSwitch (
+    rpswitch_tr,
+    rpswitch_trs,
+    rpswitch_st0,
+    rpswitch_st0r
+) where
+
+import Data.Maybe (fromJust)
+import Data.List (findIndex)
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for rpSwitchB and drpSwitchB
+------------------------------------------------------------------------------
+
+rpswitch_inp1 = (fromJust (head delta_inp), zip (repeat 1.0) (tail delta_inp))
+    where
+	delta_inp =
+            [Just (1.0, NoEvent), Nothing, Nothing,
+             Just (2.0, Event (integral:)), Just (3.0, NoEvent), Nothing,
+             Just (4.0, NoEvent), Nothing, Nothing,
+             Just (5.0, Event ((integral >>> arr (+100.0)):)),
+             Just (6.0, NoEvent), Nothing,
+             Just (7.0, NoEvent), Nothing, Nothing,
+             Just (8.0, Event tail), Just (9.0, NoEvent), Nothing]
+            ++ repeat Nothing
+
+
+-- This input contains exaples of "continuos switching", i.e. the same
+-- switching event ocurring during a a few contiguous time steps.
+-- It also starts with an immediate switch.
+rpswitch_inp2 = (fromJust (head delta_inp), zip (repeat 1.0) (tail delta_inp))
+    where
+        delta_inp =
+            [Just (1.0, Event (integral:)),
+             Just (1.0, NoEvent), Nothing,
+             Just (2.0, Event ((integral >>> arr(+100.0)):)), Nothing, Nothing,
+             Just (3.0, Event ((integral >>> arr(+200.0)):)), Nothing, Nothing,
+             Just (4.0, NoEvent), Nothing, Nothing,
+             Just (5.0, Event ((arr (*3)):)),
+             Just (5.0, NoEvent), Nothing,
+             Just (6.0, Event tail), Just (7.0, Event ((arr (*7)):)),
+             Just (8.0, Event (take 2)),
+             Just (9.0, NoEvent), Nothing]
+            ++ repeat Nothing
+
+
+rpswitch_t0 :: [[Double]]
+rpswitch_t0 = take 20 $ embed (rpSwitchB []) rpswitch_inp1
+
+rpswitch_t0r =
+    [[],		-- 0 s
+     [],		-- 1 s
+     [],		-- 2 s
+     [0.0],		-- 3 s
+     [2.0],		-- 4 s
+     [5.0],		-- 5 s
+     [8.0],		-- 6 s
+     [12.0],		-- 7 s
+     [16.0],		-- 8 s
+     [100.0, 20.0],	-- 9 s
+     [105.0, 25.0],	-- 10 s
+     [111.0, 31.0],	-- 11 s
+     [117.0, 37.0],	-- 12 s
+     [124.0, 44.0],	-- 13 s
+     [131.0, 51.0],	-- 14 s
+     [58.0],		-- 15 s
+     [66.0],		-- 16 s
+     [75.0],		-- 17 s
+     [84.0],		-- 18 s
+     [93.0]]		-- 19 s
+
+
+rpswitch_t1 :: [[Double]]
+rpswitch_t1 = take 20 $ embed (drpSwitchB []) rpswitch_inp1
+
+rpswitch_t1r =
+    [[],		-- 0 s
+     [],		-- 1 s
+     [],		-- 2 s
+     [],		-- 3 s
+     [2.0],		-- 4 s
+     [5.0],		-- 5 s
+     [8.0],		-- 6 s
+     [12.0],		-- 7 s
+     [16.0],		-- 8 s
+     [20.0]	,	-- 9 s
+     [105.0, 25.0],	-- 10 s
+     [111.0, 31.0],	-- 11 s
+     [117.0, 37.0],	-- 12 s
+     [124.0, 44.0],	-- 13 s
+     [131.0, 51.0],	-- 14 s
+     [138.0, 58.0],	-- 15 s
+     [66.0],		-- 16 s
+     [75.0],		-- 17 s
+     [84.0],		-- 18 s
+     [93.0]]		-- 19 s
+
+
+rpswitch_t2 :: [[Double]]
+rpswitch_t2 = take 20 $ embed (rpSwitchB []) rpswitch_inp2
+
+rpswitch_t2r =
+    [[0.0],							-- 0 s
+     [1.0],							-- 1 s
+     [2.0],							-- 2 s
+     [100.0, 3.0],						-- 3 s
+     [100.0, 102.0, 5.0],					-- 4 s
+     [100.0, 102.0, 104.0, 7.0],				-- 5 s
+     [200.0, 102.0, 104.0, 106.0, 9.0],				-- 6 s
+     [200.0, 203.0, 105.0, 107.0, 109.0, 12.0],			-- 7 s
+     [200.0, 203.0, 206.0, 108.0, 110.0, 112.0, 15.0],		-- 8 s
+     [203.0, 206.0, 209.0, 111.0, 113.0, 115.0, 18.0],		-- 9 s
+     [207.0, 210.0, 213.0, 115.0, 117.0, 119.0, 22.0],		-- 10 s
+     [211.0, 214.0, 217.0, 119.0, 121.0, 123.0, 26.0],		-- 11 s
+     [15.0, 215.0, 218.0, 221.0, 123.0, 125.0, 127.0, 30.0],	-- 12 s
+     [15.0, 220.0, 223.0, 226.0, 128.0, 130.0, 132.0, 35.0],	-- 13 s
+     [15.0, 225.0, 228.0, 231.0, 133.0, 135.0, 137.0, 40.0],	-- 14 s
+     [230.0, 233.0, 236.0, 138.0, 140.0, 142.0, 45.0],		-- 15 s
+     [49.0, 236.0, 239.0, 242.0, 144.0, 146.0, 148.0, 51.0],	-- 16 s
+     [56.0, 243.0],						-- 17 s
+     [63.0, 251.0],						-- 18 s
+     [63.0, 260.0]]						-- 19 s
+
+
+rpswitch_t3 :: [[Double]]
+rpswitch_t3 = take 20 $ embed (drpSwitchB []) rpswitch_inp2
+
+rpswitch_t3r =
+    [[],							-- 0 s
+     [1.0],							-- 1 s
+     [2.0],							-- 2 s
+     [3.0],							-- 3 s
+     [102.0, 5.0],						-- 4 s
+     [102.0, 104.0, 7.0],					-- 5 s
+     [102.0, 104.0, 106.0, 9.0],				-- 6 s
+     [203.0, 105.0, 107.0, 109.0, 12.0],			-- 7 s
+     [203.0, 206.0, 108.0, 110.0, 112.0, 15.0],			-- 8 s
+     [203.0, 206.0, 209.0, 111.0, 113.0, 115.0, 18.0],		-- 9 s
+     [207.0, 210.0, 213.0, 115.0, 117.0, 119.0, 22.0],		-- 10 s
+     [211.0, 214.0, 217.0, 119.0, 121.0, 123.0, 26.0],		-- 11 s
+     [215.0, 218.0, 221.0, 123.0, 125.0, 127.0, 30.0],		-- 12 s
+     [15.0, 220.0, 223.0, 226.0, 128.0, 130.0, 132.0, 35.0],	-- 13 s
+     [15.0, 225.0, 228.0, 231.0, 133.0, 135.0, 137.0, 40.0],	-- 14 s
+     [18.0, 230.0, 233.0, 236.0, 138.0, 140.0, 142.0, 45.0],	-- 15 s
+     [236.0, 239.0, 242.0, 144.0, 146.0, 148.0, 51.0],		-- 16 s
+     [56.0, 243.0, 246.0, 249.0, 151.0, 153.0, 155.0, 58.0],	-- 17 s
+     [63.0, 251.0],						-- 18 s
+     [63.0, 260.0]]						-- 19 s
+
+
+-- Starts three "ramps" with different phase. As soon as one exceeds a
+-- threshold, it's restarted, while the others are left alone. The observaton
+-- of the output is done via a loop, thus the  use of a delayed switch is
+-- essential.
+
+rpswitch_ramp :: Double -> SF a Double
+rpswitch_ramp phase = constant 2.0 >>> integral >>> arr (+phase)
+
+-- We assume that only one signal function will reach the limit at a time.
+rpswitch_limit :: Double -> SF [Double] (Event ([SF a Double]->[SF a Double]))
+rpswitch_limit x = arr (findIndex (>=x)) >>> edgeJust >>> arr (fmap restart)
+    where
+	restart n = \sfs -> take n sfs ++ [rpswitch_ramp 0.0] ++ drop (n+1) sfs
+
+rpswitch_t4 :: [[Double]]
+rpswitch_t4 = take 30 $ embed (loop sf) (deltaEncode 0.1 (repeat ()))
+    where
+        sf :: SF (a, [Double]) ([Double],[Double])
+	sf = (second (rpswitch_limit 2.99)
+	      >>> drpSwitchB [rpswitch_ramp 0.0,
+			      rpswitch_ramp 1.0,
+			      rpswitch_ramp 2.0])
+	     >>> arr dup
+
+rpswitch_t4r =
+    [[0.0, 1.0, 2.0],
+     [0.2, 1.2, 2.2],
+     [0.4, 1.4, 2.4],
+     [0.6, 1.6, 2.6],
+     [0.8, 1.8, 2.8],
+     [1.0, 2.0, 3.0],
+     [1.2, 2.2, 0.2],
+     [1.4, 2.4, 0.4],
+     [1.6, 2.6, 0.6],
+     [1.8, 2.8, 0.8],
+     [2.0, 3.0, 1.0],
+     [2.2, 0.2, 1.2],
+     [2.4, 0.4, 1.4],
+     [2.6, 0.6, 1.6],
+     [2.8, 0.8, 1.8],
+     [3.0, 1.0, 2.0],
+     [0.2, 1.2, 2.2],
+     [0.4, 1.4, 2.4],
+     [0.6, 1.6, 2.6],
+     [0.8, 1.8, 2.8],
+     [1.0, 2.0, 3.0],
+     [1.2, 2.2, 0.2],
+     [1.4, 2.4, 0.4],
+     [1.6, 2.6, 0.6],
+     [1.8, 2.8, 0.8],
+     [2.0, 3.0, 1.0],
+     [2.2, 0.2, 1.2],
+     [2.4, 0.4, 1.4],
+     [2.6, 0.6, 1.6],
+     [2.8, 0.8, 1.8]]
+
+
+rpswitch_trs =
+    [ rpswitch_t0 ~= rpswitch_t0r,
+      rpswitch_t1 ~= rpswitch_t1r,
+      rpswitch_t2 ~= rpswitch_t2r,
+      rpswitch_t3 ~= rpswitch_t3r,
+      rpswitch_t4 ~= rpswitch_t4r
+    ]
+
+rpswitch_tr = and rpswitch_trs
+
+
+rpswitch_st0 = testSFSpaceLeak 1000000 (loop sf)
+    where
+        sf :: SF (a, [Double]) ([Double],[Double])
+	sf = (second (rpswitch_limit 2.99)
+	      >>> drpSwitchB [rpswitch_ramp 0.0,
+			      rpswitch_ramp 1.0,
+			      rpswitch_ramp 2.0])
+	     >>> arr dup
+
+rpswitch_st0r = [1.5,2.5,0.5]
diff --git a/tests/TestsRSwitch.hs b/tests/TestsRSwitch.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsRSwitch.hs
@@ -0,0 +1,144 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsRSwitch.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsRSwitch				                         *
+*       Purpose:        Test cases for rSwitch and drSwitch		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsRSwitch (
+    rswitch_tr,
+    rswitch_trs,
+    rswitch_st0,
+    rswitch_st0r
+) where
+
+import Data.Maybe (fromJust)
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for rSwitch and drSwitch
+------------------------------------------------------------------------------
+
+rswitch_inp1 = (fromJust (head delta_inp), zip (repeat 1.0) (tail delta_inp))
+    where
+	delta_inp =
+            [Just (1.0, NoEvent), Nothing, Nothing,
+             Just (2.0, Event (arr (*3))), Just (3.0, NoEvent), Nothing,
+             Just (4.0, NoEvent), Nothing, Nothing,
+             Just (5.0, Event integral),
+             Just (6.0, NoEvent), Nothing,
+             Just (7.0, NoEvent), Nothing, Nothing,
+             Just (8.0, Event (arr (*7))), Just (9.0, NoEvent), Nothing]
+            ++ repeat Nothing
+
+
+-- This input contains exaples of "continuos switching", i.e. the same
+-- switching event ocurring during a a few contiguous time steps.
+-- It also starts with an immediate switch.
+rswitch_inp2 = (fromJust (head delta_inp), zip (repeat 1.0) (tail delta_inp))
+    where
+        delta_inp =
+            [Just (1.0, Event integral),
+             Just (1.0, NoEvent), Nothing,
+             Just (2.0, Event (arr (*2))), Nothing, Nothing,
+             Just (3.0, Event integral), Nothing, Nothing,
+             Just (4.0, NoEvent), Nothing, Nothing,
+             Just (5.0, Event integral),
+             Just (5.0, NoEvent), Nothing,
+             Just (6.0, Event (arr (*3))), Just (7.0, Event (arr (*4))),
+             Just (8.0, Event integral),
+             Just (9.0, NoEvent), Nothing]
+            ++ repeat Nothing
+
+
+rswitch_t0 = take 20 $ embed (rSwitch (arr (+3))) rswitch_inp1
+
+-- Integration using rectangle rule assumed.
+rswitch_t0r :: [Double]
+rswitch_t0r =
+    [4.0,  4.0,  4.0,  6.0,  9.0,
+     9.0,  12.0, 12.0, 12.0, 0.0,
+     5.0,  11.0, 17.0, 24.0, 31.0,
+     56.0, 63.0, 63.0, 63.0, 63.0]
+
+
+rswitch_t1 = take 20 $ embed (rSwitch integral) rswitch_inp1
+
+-- Integration using rectangle rule assumed.
+rswitch_t1r :: [Double]
+rswitch_t1r =
+    [0.0,  1.0,  2.0,  6.0,  9.0,
+     9.0,  12.0, 12.0, 12.0, 0.0,
+     5.0,  11.0, 17.0, 24.0, 31.0,
+     56.0, 63.0, 63.0, 63.0, 63.0]
+
+rswitch_t2 = take 20 $ embed (rSwitch (arr (+100))) rswitch_inp2
+
+-- Integration using rectangle rule assumed.
+rswitch_t2r :: [Double]
+rswitch_t2r =
+    [0.0,  1.0,  2.0, 4.0, 4.0,
+     4.0,  0.0,  0.0, 0.0, 3.0,
+     7.0,  11.0, 0.0, 5.0, 10.0,
+     18.0, 28.0, 0.0, 8.0, 17.0]
+
+
+rswitch_t3 = take 20 $ embed (drSwitch (arr (+100))) rswitch_inp2
+
+-- Integration using rectangle rule assumed.
+rswitch_t3r :: [Double]
+rswitch_t3r =
+    [101.0, 1.0,  2.0,  3.0, 4.0,
+     4.0,   6.0,  3.0,  3.0, 3.0,
+     7.0,   11.0, 15.0, 5.0, 10.0,
+     15.0,  21.0, 32.0, 8.0, 17.0]
+
+
+rswitch_sawTooth :: SF a Double
+rswitch_sawTooth =
+    loop (second (arr (>=5.0)
+                  >>> edge
+                  >>> arr (`tag` ramp))
+          >>> drSwitch ramp
+          >>> arr dup)
+    where
+        ramp :: SF a Double
+        ramp = constant 1.0 >>> integral
+
+rswitch_inp3 = deltaEncode 0.5 (repeat 0.0)
+
+rswitch_t4 = take 40 $ embed rswitch_sawTooth rswitch_inp3
+
+rswitch_t4r =
+    [0.0, 0.5, 1.0, 1.5, 2.0,
+     2.5, 3.0, 3.5, 4.0, 4.5,
+     5.0, 0.5, 1.0, 1.5, 2.0,
+     2.5, 3.0, 3.5, 4.0, 4.5,
+     5.0, 0.5, 1.0, 1.5, 2.0,
+     2.5, 3.0, 3.5, 4.0, 4.5,
+     5.0, 0.5, 1.0, 1.5, 2.0,
+     2.5, 3.0, 3.5, 4.0, 4.5]
+
+rswitch_trs =
+    [ rswitch_t0 ~= rswitch_t0r,
+      rswitch_t1 ~= rswitch_t1r,
+      rswitch_t2 ~= rswitch_t2r,
+      rswitch_t3 ~= rswitch_t3r,
+      rswitch_t4 ~= rswitch_t4r
+    ]
+
+rswitch_tr = and rswitch_trs
+
+
+rswitch_st0 = testSFSpaceLeak 2000000 rswitch_sawTooth
+rswitch_st0r = 4.75
diff --git a/tests/TestsReact.hs b/tests/TestsReact.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsReact.hs
@@ -0,0 +1,71 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsReact.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsReact					                         *
+*       Purpose:        Test cases for reactimation			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsReact (react_tr, react_trs) where
+
+import System.IO.Unsafe (unsafePerformIO)
+import Data.IORef (newIORef, writeIORef, readIORef)
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for reactimation
+------------------------------------------------------------------------------
+
+react_t0 :: [(Double, Double)]
+react_t0 = unsafePerformIO $ do
+    countr   <- newIORef undefined
+    inputr   <- newIORef undefined
+    outputsr <- newIORef []
+    let init = do
+	    writeIORef countr 1
+	    let input0 = 0.0
+            writeIORef inputr input0
+	    return input0
+        sense _ = do
+	    count <- readIORef countr
+	    if count >= 5 then do
+		writeIORef countr 1
+		input <- readIORef inputr
+		let input' = input + 0.5
+		writeIORef inputr input'
+		return (0.1, Just input')
+	     else do
+		writeIORef countr (count + 1)
+		return (0.1, Nothing)
+	actuate _ output = do
+	    outputs <- readIORef outputsr
+	    writeIORef outputsr (output : outputs)
+	    input <- readIORef inputr
+	    return (input > 5.0)
+    reactimate init sense actuate (arr dup >>> second integral)
+    outputs <- readIORef outputsr
+    return (take 25 (reverse outputs))
+
+
+react_t0r :: [(Double, Double)]
+react_t0r = [
+    (0.0,0.00), (0.0,0.00), (0.0,0.00), (0.0,0.00), (0.0,0.00),
+    (0.5,0.00), (0.5,0.05), (0.5,0.10), (0.5,0.15), (0.5,0.20),
+    (1.0,0.25), (1.0,0.35), (1.0,0.45), (1.0,0.55), (1.0,0.65),
+    (1.5,0.75), (1.5,0.90), (1.5,1.05), (1.5,1.20), (1.5,1.35),
+    (2.0,1.50), (2.0,1.70), (2.0,1.90), (2.0,2.10), (2.0,2.30)]
+
+
+react_trs = [ react_t0 ~= react_t0r ]
+
+
+react_tr = and react_trs
diff --git a/tests/TestsSscan.hs b/tests/TestsSscan.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsSscan.hs
@@ -0,0 +1,473 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id$
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsSscan					                         *
+*       Purpose:        Test cases for pre sscan	     		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*             Copyright (c) University of Nottingham, 2005                   *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsSscan (sscan_tr, sscan_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases sscan
+------------------------------------------------------------------------------
+
+-- pre and iPre in terms of sscan
+pre_sscan :: SF a a
+pre_sscan = sscanPrim f uninit uninit
+    where
+        f c a = Just (a, c)
+        uninit = error "pre_sscan: Uninitialized pre operator."
+
+iPre_sscan :: a -> SF a a
+iPre_sscan = (--> pre_sscan)
+
+
+sscan_t0, sscan_t0r :: [Double]
+sscan_t0 = testSF1 (iPre_sscan 17)
+sscan_t0r =
+    [17.0,0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,
+     15.0,16.0,17.0,18.0,19.0,20.0,21.0,22.0,23.0]
+
+
+sscan_t1, sscan_t1r :: [Double]
+sscan_t1 = testSF2 (iPre_sscan 17)
+sscan_t1r =
+    [17.0,0.0,0.0,0.0,0.0,0.0,1.0,1.0,1.0,1.0,1.0,2.0,2.0,2.0,2.0,2.0,
+     3.0,3.0,3.0,3.0,3.0,4.0,4.0,4.0,4.0]
+
+
+sscan_t2, sscan_t2r :: [Double]
+sscan_t2 = testSF1 (time
+                    >>> arr (\t -> sin (0.5 * t * pi + pi))
+                    >>> loop (arr (\(x1,x2) -> let x' = max x1 x2 in (x',x'))
+                              >>> second (iPre_sscan 0.0)))
+sscan_t2r =
+    take 25
+         (let xs = [ sin (0.5 * t * pi + pi) | t <- [0.0, 0.25 ..] ]
+          in tail (scanl max 0 xs))
+
+
+
+sscan_t3, sscan_t3r :: [Double]
+sscan_t3 = testSF1 (time
+                    >>> arr (\t -> sin (0.5 * t * pi + pi))
+                    >>> sscan max 0.0)
+
+sscan_t3r =
+    take 25
+         (let xs = [ sin (0.5 * t * pi + pi) | t <- [0.0, 0.25 ..] ]
+          in tail (scanl max 0 xs))
+
+
+hold_sscan :: a -> SF (Event a) a
+hold_sscan a = sscanPrim f () a
+    where
+        f _ NoEvent   = Nothing
+        f _ (Event a) = Just ((), a)
+
+
+dHold_sscan :: a -> SF (Event a) a
+dHold_sscan a = hold_sscan a >>> iPre_sscan a
+
+
+-- This is a (somewhat strange) way of doing a counter that
+-- stops after reaching a threshold. Note that the ingoing event
+-- is *control dependent* on the output of the counter, so
+-- "dHold" really has to have the capability of delivering an
+-- output without looking at the current input at all.
+sscan_t4, sscan_t4r :: [Int]
+sscan_t4 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = repeatedly 1.0 ()
+             >>> (loop $
+                      arr (\(e,c) -> (e `tag` (c + 1)) `gate` (c < 10))
+                      >>> dHold_sscan 0
+                      >>> arr dup)
+sscan_t4r = [0,0,0,0,		-- 0s
+             0,1,1,1,		-- 1s
+             1,2,2,2,		-- 2s
+             2,3,3,3,		-- 3s
+             3,4,4,4,		-- 4s
+             4,5,5,5,		-- 5s
+             5,6,6,6,		-- 6s
+             6,7,7,7,		-- 7s
+             7,8,8,8,		-- 8s
+             8,9,9,9,		-- 9s
+             9,10,10,10,	-- 10s
+             10,10,10,10,	-- 11s
+             10,10]		-- 12s
+
+-- Version of the above that tests that thigs still work OK also if
+-- there is an initial event.
+sscan_t5, sscan_t5r :: [Int]
+sscan_t5 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = (now () &&& repeatedly 1.0 ()) >>> arr (uncurry lMerge)
+             >>> (loop $
+                      arr (\(e,c) -> (e `tag` (c + 1)) `gate` (c < 10))
+                      >>> dHold_sscan 0
+                      >>> arr dup)
+sscan_t5r = [0,1,1,1,		-- 0s
+             1,2,2,2,		-- 1s
+             2,3,3,3,		-- 2s
+             3,4,4,4,		-- 3s
+             4,5,5,5,		-- 4s
+             5,6,6,6,		-- 5s
+             6,7,7,7,		-- 6s
+             7,8,8,8,		-- 7s
+             8,9,9,9,		-- 8s
+             9,10,10,10,	-- 9s
+             10,10,10,10,	-- 10s
+             10,10,10,10,	-- 11s
+             10,10]		-- 12s
+
+
+-- Version of the sscan_t4 in terms of sscan
+sscan_t6, sscan_t6r :: [Int]
+sscan_t6 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = repeatedly 1.0 () >>> (sscanPrim f 0 0)
+
+        f c NoEvent               = Nothing
+        f c (Event _) | c < 10    = Just (c', c')
+                      | otherwise = Nothing
+            where
+	        c' = c + 1
+
+
+sscan_t6r = [0,0,0,0,		-- 0s
+             1,1,1,1,		-- 1s
+             2,2,2,2,		-- 2s
+             3,3,3,3,		-- 3s
+             4,4,4,4,		-- 4s
+             5,5,5,5,		-- 5s
+             6,6,6,6,		-- 6s
+             7,7,7,7,		-- 7s
+             8,8,8,8,		-- 8s
+             9,9,9,9,		-- 9s
+             10,10,10,10,	-- 10s
+             10,10,10,10,	-- 11s
+             10,10]		-- 12s
+
+-- Version of sscan_t5 directly in terms of sscan.
+sscan_t7, sscan_t7r :: [Int]
+sscan_t7 = take 50 (embed sf (deltaEncode 0.25 (repeat ())))
+    where
+        sf = (now () &&& repeatedly 1.0 ()) >>> arr (uncurry lMerge)
+             >>> (sscanPrim f 0 0)
+
+        f c NoEvent               = Nothing
+        f c (Event _) | c < 10    = Just (c', c')
+                      | otherwise = Nothing
+            where
+	        c' = c + 1
+
+
+sscan_t7r = [1,1,1,1,		-- 0s
+             2,2,2,2,		-- 1s
+             3,3,3,3,		-- 2s
+             4,4,4,4,		-- 3s
+             5,5,5,5,		-- 4s
+             6,6,6,6,		-- 5s
+             7,7,7,7,		-- 6s
+             8,8,8,8,		-- 7s
+             9,9,9,9,		-- 8s
+             10,10,10,10,	-- 9s
+             10,10,10,10,	-- 10s
+             10,10,10,10,	-- 11s
+             10,10]		-- 12s
+
+
+edge_sscan :: SF Bool (Event ())
+edge_sscan = sscanPrim f 2 NoEvent
+    where
+        f 0 False = Nothing
+        f 0 True  = Just (1, Event ())
+        f 1 False = Just (0, NoEvent)
+        f 1 True  = Just (2, NoEvent)
+        f 2 False = Just (0, NoEvent)
+        f 2 True  = Nothing
+
+
+sscan_t8 :: [Event ()]
+sscan_t8 = testSF1 (localTime >>> arr (>=0) >>> edge_sscan)
+
+sscan_t8r =
+    [NoEvent, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent,	NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, NoEvent,	NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent,	NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+sscan_t9 :: [Event ()]
+sscan_t9 = testSF1 (localTime >>> arr (>=4.26) >>> edge_sscan)
+
+sscan_t9r =
+    [NoEvent, NoEvent, NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, Event (), NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+edgeBy_sscan :: (a -> a -> Maybe b) -> a -> SF a (Event b)
+edgeBy_sscan f a = sscanPrim g a NoEvent
+    where
+        g a_prev a = Just (a, maybeToEvent (f a_prev a))
+
+
+-- Raising edge detector.
+sscan_isEdge False False = Nothing
+sscan_isEdge False True  = Just ()
+sscan_isEdge True  True  = Nothing
+sscan_isEdge True  False = Nothing
+
+
+sscan_t10 :: [Event ()]
+sscan_t10 = testSF1 (localTime
+                     >>> arr (>=0)
+                     >>> edgeBy_sscan sscan_isEdge False)
+
+sscan_t10r =
+    [Event (), NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent,  NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+sscan_t11 :: [Event ()]
+sscan_t11 = testSF1 (localTime
+                     >>> arr (>=4.26)
+                     >>> edgeBy_sscan sscan_isEdge False)
+
+sscan_t11r =
+    [NoEvent, NoEvent, NoEvent,  NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent,  NoEvent,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, Event (), NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent,	 NoEvent,	-- 5.0 s
+     NoEvent]
+
+-- Raising and falling edge detector.
+sscan_isEdge2 False False = Nothing
+sscan_isEdge2 False True  = Just True
+sscan_isEdge2 True  True  = Nothing
+sscan_isEdge2 True  False = Just False
+
+sscan_t12 :: [Event Bool]
+sscan_t12 = testSF1 (localTime
+                    >>> arr (\t -> t >=2.01 && t <= 4.51)
+		    >>> edgeBy_sscan sscan_isEdge2 True)
+
+sscan_t12r =
+    [Event False, NoEvent,    NoEvent, NoEvent,		-- 0.0 s
+     NoEvent,     NoEvent,    NoEvent, NoEvent,		-- 1.0 s
+     NoEvent,     Event True, NoEvent, NoEvent,		-- 2.0 s
+     NoEvent,     NoEvent,    NoEvent, NoEvent,		-- 3.0 s
+     NoEvent,     NoEvent,    NoEvent, Event False,	-- 4.0 s
+     NoEvent,     NoEvent,    NoEvent, NoEvent,		-- 5.0 s
+     NoEvent]
+
+
+
+smaximum_sscan :: Ord a => SF a a
+smaximum_sscan =
+    switch (identity &&& now () >>> arr (\(a,e) -> (a, e `tag` a)))
+           (\a0 -> sscanPrim (\c a -> if a > c
+                                      then (Just (a,a))
+                                      else Nothing)
+                             a0 a0)
+
+
+sscan_t13, sscan_t13r :: [Double]
+sscan_t13 = take 100 (embed sf (deltaEncode 0.1 (repeat ())))
+    where
+        sf = time
+             >>> arr (\t -> (t + 1) * cos (pi * t + pi))
+             >>> smaximum_sscan
+
+sscan_t13r =
+    take 100
+         (let xs = [ (t + 1) * cos (pi * t + pi) | t <- [0.0, 0.1 ..] ]
+          in tail (scanl max (-100) xs))
+
+
+-- Some tests of signal functions that may be implemented using sscan
+-- internally and their combinations with other sscan-based signal
+-- functions and event processors.
+
+sscan_t14, sscan_t14r :: [Event Int]
+sscan_t14 = take 100 (embed sf (deltaEncode 0.1 (repeat ())))
+    where
+        sf :: SF () (Event Int)
+        sf = time >>> arr (\t -> sin (2 * t))
+             >>> arr (>0)
+             >>> edge
+             >>> arr (`tag` (+1))
+             >>> accum 0
+
+sscan_t14r =
+    [NoEvent,Event 1,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,Event 2,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,Event 3,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     Event 4,NoEvent,NoEvent,NoEvent,NoEvent]
+
+sscan_t15, sscan_t15r :: [Int]
+sscan_t15 = take 100 (embed sf (deltaEncode 0.1 (repeat ())))
+    where
+        sf :: SF () Int
+        sf = time >>> arr (\t -> sin (2 * t))
+             >>> arr (>0)
+             >>> edge
+             >>> arr (`tag` (+1))
+             >>> accumHold 0
+
+sscan_t15r =
+    [0,1,1,1,1,1,1,1,1,1,
+     1,1,1,1,1,1,1,1,1,1,
+     1,1,1,1,1,1,1,1,1,1,
+     1,1,2,2,2,2,2,2,2,2,
+     2,2,2,2,2,2,2,2,2,2,
+     2,2,2,2,2,2,2,2,2,2,
+     2,2,2,3,3,3,3,3,3,3,
+     3,3,3,3,3,3,3,3,3,3,
+     3,3,3,3,3,3,3,3,3,3,
+     3,3,3,3,3,4,4,4,4,4]
+
+sscan_t16, sscan_t16r :: [Int]
+sscan_t16 = take 100 (embed sf (deltaEncode 0.1 (repeat ())))
+    where
+        sf :: SF () Int
+        sf = time >>> arr (\t -> sin (2 * t))
+             >>> arr (>0)
+             >>> edge
+             >>> arr (`tag` (+1))
+             >>> dAccumHold 0
+
+sscan_t16r =
+    [0,0,1,1,1,1,1,1,1,1,
+     1,1,1,1,1,1,1,1,1,1,
+     1,1,1,1,1,1,1,1,1,1,
+     1,1,1,2,2,2,2,2,2,2,
+     2,2,2,2,2,2,2,2,2,2,
+     2,2,2,2,2,2,2,2,2,2,
+     2,2,2,2,3,3,3,3,3,3,
+     3,3,3,3,3,3,3,3,3,3,
+     3,3,3,3,3,3,3,3,3,3,
+     3,3,3,3,3,3,4,4,4,4]
+
+sscan_t17, sscan_t17r :: [Event Int]
+sscan_t17 = take 100 (embed sf (deltaEncode 0.1 (repeat ())))
+    where
+        sf :: SF () (Event Int)
+        sf = time >>> arr (\t -> sin (2 * t))
+             >>> arr (>0)
+             >>> iPre False
+             >>> edge
+             >>> arr (`tag` (+1))
+             >>> accum 0
+
+sscan_t17r =
+    [NoEvent,NoEvent,Event 1,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,Event 2,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,Event 3,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,NoEvent,NoEvent,NoEvent,NoEvent,
+     NoEvent,Event 4,NoEvent,NoEvent,NoEvent]
+
+sscan_t18, sscan_t18r :: [Int]
+sscan_t18 = take 100 (embed sf (deltaEncode 0.1 (repeat ())))
+    where
+        sf :: SF () Int
+        sf = time >>> arr (\t -> sin (2 * t))
+             >>> arr (>0)
+             >>> iPre False
+             >>> edge
+             >>> arr (`tag` (+1))
+             >>> accumHold 0
+
+sscan_t18r =
+    [0,0,1,1,1,1,1,1,1,1,
+     1,1,1,1,1,1,1,1,1,1,
+     1,1,1,1,1,1,1,1,1,1,
+     1,1,1,2,2,2,2,2,2,2,
+     2,2,2,2,2,2,2,2,2,2,
+     2,2,2,2,2,2,2,2,2,2,
+     2,2,2,2,3,3,3,3,3,3,
+     3,3,3,3,3,3,3,3,3,3,
+     3,3,3,3,3,3,3,3,3,3,
+     3,3,3,3,3,3,4,4,4,4]
+
+sscan_trs =
+    [ sscan_t0 ~= sscan_t0r,
+      sscan_t1 ~= sscan_t1r,
+      sscan_t2 ~= sscan_t2r,
+      sscan_t3 ~= sscan_t3r,
+      sscan_t4 == sscan_t4r,
+      sscan_t5 == sscan_t5r,
+      sscan_t6 == sscan_t6r,
+      sscan_t7 == sscan_t7r,
+      sscan_t8 == sscan_t8r,
+      sscan_t9 == sscan_t9r,
+      sscan_t10 == sscan_t10r,
+      sscan_t11 == sscan_t11r,
+      sscan_t12 == sscan_t12r,
+      sscan_t13 ~= sscan_t13r,
+      sscan_t14 ~= sscan_t14r,
+      sscan_t15 ~= sscan_t15r,
+      sscan_t16 ~= sscan_t16r,
+      sscan_t17 ~= sscan_t17r,
+      sscan_t18 ~= sscan_t18r
+    ]
+
+sscan_tr = and sscan_trs
diff --git a/tests/TestsSwitch.hs b/tests/TestsSwitch.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsSwitch.hs
@@ -0,0 +1,214 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsSwitch.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsSwitch					                         *
+*       Purpose:        Test cases for switch				     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+module TestsSwitch (switch_tr, switch_trs) where
+
+import FRP.Yampa
+import FRP.Yampa.EventS
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for switch and dSwitch
+------------------------------------------------------------------------------
+
+switch_inp1 = deltaEncode 1.0 $
+    [1.0, 1.0, 1.0,
+     2.0,
+     3.0, 3.0,
+     4.0, 4.0, 4.0,
+     5.0,
+     6.0, 6.0,
+     7.0, 7.0, 7.0,
+     8.0]
+     ++ repeat 9.0
+
+switch_t0 = take 18 $
+    embed (switch switch_t0a $ \x ->
+           switch (switch_t0b x) $ \x ->
+	   switch (switch_t0c x) $ \x ->
+	   switch (switch_t0c x) $ \x ->
+	   switch (switch_t0d x) $ \x ->
+	   switch (switch_t0e x) $ \x ->
+	   switch (switch_t0e x) $
+           switch_t0final)
+	  switch_inp1
+
+switch_t0a :: SF Double (Double, Event Int)
+switch_t0a = localTime
+             >>> arr dup
+             >>> second (arr (>= 3.0) >>> edge >>> arr (`tag` 17))
+
+switch_t0b :: Int -> SF Double (Double, Event Int)
+switch_t0b x = localTime
+               >>> arr dup
+               >>> second (arr (>= 3.0) >>> edge >>> arr (`tag` (23 + x)))
+
+-- This should raise an event IMMEDIATELY: no time should pass.
+switch_t0c :: Num b => b -> SF a (a, Event b)
+switch_t0c x = arr dup >>> second (now (x + 1))
+
+switch_t0d x = (arr (+ (fromIntegral x))) &&& (arr (>= 7.0) >>> edge)
+
+-- This should raise an event IMMEDIATELY: no time should pass.
+switch_t0e :: b -> SF a (a, Event a)
+switch_t0e _ = arr dup >>> second snap
+
+switch_t0final :: Double -> SF Double Double
+switch_t0final x = arr (+x)
+
+switch_t0r =
+    [0.0,  1.0,  2.0, 				-- switch_t0a
+     0.0,  1.0,  2.0,   			-- switch_t0b
+     46.0, 46.0, 46.0, 47.0, 48.0, 48.0,	-- switch_t0d
+     14.0, 14.0, 14.0, 15.0, 16.0, 16.0		-- switch_t0final
+    ]
+
+
+switch_t1 = take 32 $ embed (switch_t1rec 42.0) switch_inp1
+
+-- Outputs current input, local time, and the value of the initializing
+-- argument until some time has passed (determined by integrating a constant),
+-- at which point an event occurs.
+switch_t1a :: Double -> SF Double ((Double,Double,Double), Event ())
+switch_t1a x = (arr dup >>> second localTime >>> arr (\(a,t) -> (a,t,x)))
+	       &&& (constant 0.5
+                    >>> integral
+                    >>> (arr (>= (2.0 :: Double)) -- Used to work with no sig.
+                    >>> edge))
+
+-- This should raise an event IMMEDIATELY: no time should pass.
+switch_t1b :: b -> SF a ((Double,Double,Double), Event a)
+switch_t1b _ = constant (-999.0,-999.0,-999.0) &&& snap
+
+switch_t1rec :: Double -> SF Double (Double,Double,Double)
+switch_t1rec x =
+    switch (switch_t1a x) $ \x ->
+    switch (switch_t1b x) $ \x ->
+    switch (switch_t1b x) $
+    switch_t1rec
+
+switch_t1r =
+    [(1.0,0.0,42.0), (1.0,1.0,42.0), (1.0,2.0,42.0), (2.0,3.0,42.0),
+     (3.0,0.0,3.0),  (3.0,1.0,3.0),  (4.0,2.0,3.0),  (4.0,3.0,3.0),
+     (4.0,0.0,4.0),  (5.0,1.0,4.0),  (6.0,2.0,4.0),  (6.0,3.0,4.0),
+     (7.0,0.0,7.0),  (7.0,1.0,7.0),  (7.0,2.0,7.0),  (8.0,3.0,7.0),
+     (9.0,0.0,9.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0),
+     (9.0,0.0,9.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0),
+     (9.0,0.0,9.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0),
+     (9.0,0.0,9.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0)]
+
+switch_t2 = take 18 $
+    embed (dSwitch switch_t0a $ \x ->
+           dSwitch (switch_t0b x) $ \x ->
+           dSwitch (switch_t0c x) $ \x ->
+           dSwitch (switch_t0c x) $ \x ->
+	   dSwitch (switch_t0d x) $ \x ->
+	   dSwitch (switch_t0e x) $ \x ->
+	   dSwitch (switch_t0e x) $
+           switch_t0final)
+	  switch_inp1
+
+switch_t2r =
+    [0.0,  1.0,  2.0,				-- switch_t0a
+     3.0,  1.0,  2.0,				-- switch_t0b
+     3.0,  46.0, 46.0, 47.0, 48.0, 48.0,	-- switch_t0d
+     49.0, 14.0, 14.0, 15.0, 16.0, 16.0		-- switch_t0final
+    ]
+
+
+switch_t3 = take 32 $ embed (switch_t3rec 42.0) switch_inp1
+
+switch_t3rec :: Double -> SF Double (Double,Double,Double)
+switch_t3rec x =
+    dSwitch (switch_t1a x) $ \x ->
+    dSwitch (switch_t1b x) $ \x ->
+    dSwitch (switch_t1b x) $
+    switch_t3rec
+
+switch_t3r =
+    [(1.0,0.0,42.0), (1.0,1.0,42.0), (1.0,2.0,42.0), (2.0,3.0,42.0),
+     (3.0,4.0,42.0), (3.0,1.0,3.0),  (4.0,2.0,3.0),  (4.0,3.0,3.0),
+     (4.0,4.0,3.0),  (5.0,1.0,4.0),  (6.0,2.0,4.0),  (6.0,3.0,4.0),
+     (7.0,4.0,4.0),  (7.0,1.0,7.0),  (7.0,2.0,7.0),  (8.0,3.0,7.0),
+     (9.0,4.0,7.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0),
+     (9.0,4.0,9.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0),
+     (9.0,4.0,9.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0),
+     (9.0,4.0,9.0),  (9.0,1.0,9.0),  (9.0,2.0,9.0),  (9.0,3.0,9.0)]
+
+
+-- The correct strictness properties of dSwitch are crucial here.
+-- switch does not work.
+switch_t4 = take 25 $
+    embed (loop $
+	       dSwitch switch_t4a $ \_ ->
+	       dSwitch switch_t4a $ \_ ->
+	       dSwitch switch_t4a $ \_ ->
+	       switch_t4final
+           )
+          (deltaEncode 1.0 (repeat ()))
+
+
+switch_t4a :: SF (a, Double) ((Double, Double), Event ())
+switch_t4a = (constant 1.0 >>> integral >>> arr dup)
+             &&& (arr (\ (_, x) -> x >= 5.0) >>> edge)
+
+switch_t4final :: SF (a, Double) (Double, Double)
+switch_t4final = constant 0.1 >>> integral >>> arr dup
+
+switch_t4r =
+    [0.0, 1.0, 2.0, 3.0, 4.0,				-- switch_t4a
+     5.0, 1.0, 2.0, 3.0, 4.0,				-- switch_t4a
+     5.0, 1.0, 2.0, 3.0, 4.0,				-- switch_t4a
+     5.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9	-- switch_t4final
+    ]
+
+
+impulseIntegral2 :: VectorSpace a s => SF (a, Event a) a
+impulseIntegral2 =
+   switch (first integral >>> arr (\(a, ea) -> (a, fmap (^+^ a) ea)))
+       impulseIntegral2'
+ where
+   impulseIntegral2' :: VectorSpace a s => a -> SF (a, Event a) a
+   impulseIntegral2' a =
+       switch ((integral >>> arr (^+^ a)) *** notYet
+               >>> arr (\(a, ea) -> (a, fmap (^+^ a) ea)))
+              impulseIntegral2'
+
+switch_t5 :: [Double]
+switch_t5 = take 50 $ embed impulseIntegral2
+			    (deltaEncode 0.1 (zip (repeat 1.0) evSeq))
+    where
+	evSeq = replicate 9 NoEvent ++ [Event 10.0]
+		++ replicate 9 NoEvent ++ [Event (-10.0)]
+		++ evSeq
+
+switch_t5r =
+    [ 0.0,  0.1,  0.2,  0.3,  0.4,  0.5,  0.6,  0.7,  0.8, 10.9,
+     11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8,  1.9,
+      2.0,  2.1,  2.2,  2.3,  2.4,  2.5,  2.6,  2.7,  2.8, 12.9,
+     13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8,  3.9,
+      4.0,  4.1,  4.2,  4.3,  4.4,  4.5,  4.6,  4.7,  4.8, 14.9]
+
+
+switch_trs =
+    [ switch_t0 ~= switch_t0r,
+      switch_t1 ~= switch_t1r,
+      switch_t2 ~= switch_t2r,
+      switch_t3 ~= switch_t3r,
+      switch_t4 ~= switch_t4r,
+      switch_t5 ~= switch_t5r
+    ]
+
+switch_tr = and switch_trs
+
diff --git a/tests/TestsTask.hs b/tests/TestsTask.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsTask.hs
@@ -0,0 +1,232 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsTask.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsTask					         *
+*       Purpose:        Test cases for tasks (Task)			     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+-- Very rudimentary testing of Task.
+
+module TestsTask (task_tr, task_trs) where
+
+import Control.Monad (when, forever)
+import FRP.Yampa
+import FRP.Yampa.Task
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for tasks (Task)
+------------------------------------------------------------------------------
+
+task_t0 = testSF1 (runTask (do
+			       mkTask (localTime
+			               &&&(localTime >>> arr (>=5.0) >>> edge))
+			       x <- snapT
+			       return (x * 2.0))
+                 )
+
+task_t0r =
+    [Left 0.0,   Left 0.25,  Left 0.5,   Left 0.75,  Left 1.0,
+     Left 1.25,  Left 1.5,   Left 1.75,  Left 2.0,   Left 2.25,
+     Left 2.5,   Left 2.75,  Left 3.0,   Left 3.25,  Left 3.5,
+     Left 3.75,  Left 4.0,   Left 4.25,  Left 4.5,   Left 4.75,
+     Right 40.0, Right 40.0, Right 40.0, Right 40.0, Right 40.0]
+
+
+task_t1 = testSF1 (runTask (do
+			       mkTask (localTime
+			               &&& (localTime>>>arr (>=5.0) >>> edge))
+			       return ()   -- No time should pass!
+			       return ()   -- No Time should pass!
+			       snapT	   -- No time should pass!
+                               snapT	   -- No time should pass!
+			       x <- snapT
+			       return (x * 2.0))
+                 )
+
+
+task_t2 = testSF1 (runTask (do
+			       sleepT 1.51 42.0
+			       x <- snapT
+			       y <- snapT
+			       sleepT 1.51 x
+			       if x == y then
+			           sleepT 1.51 (x * 2)
+				else
+				   sleepT 0.51 (x * 3)
+			  )
+		 )
+
+task_t2r =
+    [Left 42.0, Left 42.0, Left 42.0, Left 42.0,	-- 0.0 s
+     Left 42.0, Left 42.0, Left 42.0, Left 7.0,		-- 1.0 s
+     Left 7.0,	Left 7.0,  Left 7.0,  Left 7.0,		-- 2.0 s
+     Left 7.0,	Left 7.0,  Left 14.0, Left 14.0,	-- 3.0 s
+     Left 14.0,	Left 14.0, Left 14.0, Left 14.0,	-- 4.0 s
+     Left 14.0,	Right (),  Right (),  Right (),		-- 5.0 s
+     Right ()]
+
+
+task_t3 = testSF1 (runTask (do
+			      c <- sawtooth `timeOut` 3.49
+			      case c of
+			          Nothing -> sleepT 1.51 (-10.0)
+				  Just x  -> sleepT 1.51 x
+			  )
+		 )
+    where
+        sawtooth =
+	    forever ((mkTask (constant 2.0 >>> integral &&& never))
+	             `timeOut` 1.5)
+
+task_t3r :: [Either Double ()]
+task_t3r =
+    [Left 0.0,     Left 0.5,     Left 1.0,     Left 1.5,	-- 0.0 s
+     Left 2.0,     Left 2.5,     Left 0.0,     Left 0.5,	-- 1.0 s
+     Left 1.0,     Left 1.5,     Left 2.0,     Left 2.5,	-- 2.0 s
+     Left 0.0,     Left 0.5,     Left (-10.0), Left (-10.0),	-- 3.0 s
+     Left (-10.0), Left (-10.0), Left (-10.0), Left (-10.0),	-- 4.0 s
+     Left (-10.0), Right (),	 Right (),     Right (),	-- 5.0 s
+     Right ()]
+
+
+task_t4 = testSF1 (runTask (do
+			      c <- sawtooth `timeOut` 3.49
+			      case c of
+			          Nothing -> sleepT 1.51 (-10.0)
+				  Just x  -> sleepT 1.51 x
+			  )
+		 )
+    where
+        sawtooth = do
+	    for 1 (+1) (<=2)
+                ((mkTask (constant 2.0 >>> integral &&& never))
+		 `timeOut` 1.5)
+	    return (-42.0)
+
+task_t4r :: [Either Double ()]
+task_t4r =
+    [Left 0.0,     Left 0.5,     Left 1.0,     Left 1.5,	-- 0.0 s
+     Left 2.0,     Left 2.5,     Left 0.0,     Left 0.5,	-- 1.0 s
+     Left 1.0,     Left 1.5,     Left 2.0,     Left 2.5,	-- 2.0 s
+     Left (-42.0), Left (-42.0), Left (-42.0), Left (-42.0),	-- 3.0 s
+     Left (-42.0), Left (-42.0), Left (-42.0), Right (),	-- 4.0 s
+     Right (),	   Right (),	 Right (),     Right (),	-- 5.0 s
+     Right ()]
+
+
+task_t5 = testSF1 (runTask (do
+			      x<-(sawtoothCycle>>snapT) `repeatUntil` (>=20.0)
+			      y<-snapT
+			      return (x == y)
+			  )
+		 )
+    where
+	sawtoothCycle = mkTask (constant 2.0 >>> integral &&& after 1.5 ())
+
+task_t5r :: [Either Double Bool]
+task_t5r =
+    [Left 0.0, Left 0.5, Left 1.0, Left 1.5,	-- 0.0 s, 0 - 3
+     Left 2.0, Left 2.5, Left 0.0, Left 0.5,	-- 1.0 s, 4 - 7
+     Left 1.0, Left 1.5, Left 2.0, Left 2.5,	-- 2.0 s, 8 - 11
+     Left 0.0, Left 0.5, Left 1.0, Left 1.5,	-- 3.0 s, 12 - 15
+     Left 2.0, Left 2.5, Left 0.0, Left 0.5,	-- 4.0 s, 16 - 19,
+     Left 1.0, Left 1.5, Left 2.0, Left 2.5,	-- 5.0 s, 20 - 23
+     Right True]
+
+
+task_t6 = testSF1 $ runTask $
+    do
+        x <- ((sawtoothCycle >> snapT) `repeatUntil` (>=20.0))
+	     `abortWhen` (localTime >>> arr (>=3.51) >>> edge)
+        y <- snapT
+	return (x,y)
+    where
+	sawtoothCycle = mkTask (constant 2.0 >>> integral &&& after 1.5 ())
+
+task_t6r :: [Either Double (Either Double (), Double)]
+task_t6r =
+    [Left 0.0, Left 0.5, Left 1.0, Left 1.5,		-- 0.0 s, 0 - 3
+     Left 2.0, Left 2.5, Left 0.0, Left 0.5,		-- 1.0 s, 4 - 7
+     Left 1.0, Left 1.5, Left 2.0, Left 2.5,		-- 2.0 s, 8 - 11
+     Left 0.0, Left 0.5, Left 1.0, Right (Right (),15.0), -- 3.0 s, 12 - 15
+     Right (Right (),15.0), Right (Right (),15.0),	-- 4.0 s, 16, 17
+     Right (Right (),15.0), Right (Right (),15.0),	-- 4.5 s, 18, 19
+     Right (Right (),15.0), Right (Right (),15.0),	-- 5.0 s, 20, 21
+     Right (Right (),15.0), Right (Right (),15.0),	-- 5.5 s, 22, 23
+     Right (Right (),15.0)]
+
+task_t7 = testSF1 $ runTask $
+    do
+        x <- ((sawtoothCycle >> snapT) `repeatUntil` (>=20.0))
+	     `abortWhen` (localTime >>> arr (>=5.75) >>> edge)
+        y <- snapT
+	return (x,y)
+    where
+	sawtoothCycle = mkTask (constant 2.0 >>> integral &&& after 1.5 ())
+
+task_t7r :: [Either Double (Either Double (), Double)]
+task_t7r =
+    [Left 0.0, Left 0.5, Left 1.0, Left 1.5,	-- 0.0 s, 0 - 3
+     Left 2.0, Left 2.5, Left 0.0, Left 0.5,	-- 1.0 s, 4 - 7
+     Left 1.0, Left 1.5, Left 2.0, Left 2.5,	-- 2.0 s, 8 - 11
+     Left 0.0, Left 0.5, Left 1.0, Left 1.5,	-- 3.0 s, 12 - 15
+     Left 2.0, Left 2.5, Left 0.0, Left 0.5,	-- 4.0 s, 16 - 19
+     Left 1.0, Left 1.5, Left 2.0, Right (Right (),23.0), -- 5.0 s, 20 - 23
+     Right (Right (),23.0)]
+
+task_t8 = testSF1 $ runTask $
+    do
+        x <- ((sawtoothCycle >> snapT) `repeatUntil` (>=20.0))
+	     `abortWhen` (localTime >>> arr (>=5.76) >>> edge)
+        y <- snapT
+	return (x,y)
+    where
+	sawtoothCycle = mkTask (constant 2.0 >>> integral &&& after 1.5 ())
+
+-- Since abortWhen uses lMergeEvent, the terminating event of the task
+-- gets priority over the aborting event.
+task_t8r :: [Either Double (Either Double (), Double)]
+task_t8r =
+    [Left 0.0, Left 0.5, Left 1.0, Left 1.5,	-- 0.0 s, 0 - 3
+     Left 2.0, Left 2.5, Left 0.0, Left 0.5,	-- 1.0 s, 4 - 7
+     Left 1.0, Left 1.5, Left 2.0, Left 2.5,	-- 2.0 s, 8 - 11
+     Left 0.0, Left 0.5, Left 1.0, Left 1.5,	-- 3.0 s, 12 - 15
+     Left 2.0, Left 2.5, Left 0.0, Left 0.5,	-- 4.0 s, 16 - 19
+     Left 1.0, Left 1.5, Left 2.0, Left 2.5,	-- 5.0 s, 20 - 23
+     Right (Left 24.0,24.0)]
+
+task_trs =
+    [ task_t0 ~= task_t0r,
+      task_t1 ~= task_t0r,	-- Intentionally! task_t0 = task_t1!
+      task_t2 ~= task_t2r,
+      task_t3 ~= task_t3r,
+      task_t4 ~= task_t4r,
+      task_t5 ~= task_t5r,
+      task_t6 ~= task_t6r,
+      task_t7 ~= task_t7r,
+      task_t8 ~= task_t8r
+    ]
+
+task_tr = and task_trs
+
+-- | Repeat m until result satisfies the predicate p
+repeatUntil :: Monad m => m a -> (a -> Bool) -> m a
+m `repeatUntil` p = m >>= \x -> if not (p x) then repeatUntil m p else return x
+
+-- | C-style for-loop.
+--
+-- Example:
+--
+-- >>> for 0 (+1) (>=10) ...
+for :: Monad m => a -> (a -> a) -> (a -> Bool) -> m b -> m ()
+for i f p m = when (p i) $ m >> for (f i) f p m
+
diff --git a/tests/TestsUtils.hs b/tests/TestsUtils.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsUtils.hs
@@ -0,0 +1,372 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsUtils.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsUtils					         *
+*       Purpose:        Test cases for utilities (Utilities)	     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+-- Not really intended to test all definitions in the utilities module.
+
+module TestsUtils (utils_tr, utils_trs) where
+
+import FRP.Yampa
+import FRP.Yampa.Conditional
+import FRP.Yampa.EventS
+import FRP.Yampa.Hybrid
+import FRP.Yampa.Switches
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for utilities (Utils)
+------------------------------------------------------------------------------
+
+-- Should re-order these test cases to reflect the order in Utils
+-- at some point.
+
+utils_inp1 = deltaEncode 1.0 $
+    [NoEvent,   NoEvent,   Event 1.0, NoEvent,
+     Event 2.0, NoEvent,   NoEvent,   NoEvent,
+     Event 3.0, Event 4.0, Event 4.0, NoEvent,
+     Event 0.0, NoEvent,   NoEvent,   NoEvent]
+    ++ repeat NoEvent
+
+
+utils_inp2 = deltaEncode 1.0 $
+    [Event 1.0, NoEvent,   NoEvent,   NoEvent,
+     Event 2.0, NoEvent,   NoEvent,   NoEvent,
+     Event 3.0, Event 4.0, Event 4.0, NoEvent,
+     Event 0.0, NoEvent,   NoEvent,   NoEvent]
+    ++ repeat NoEvent
+
+
+utils_t0 :: [Double]
+utils_t0 = take 16 $ embed (dHold 99.99) utils_inp1
+
+utils_t0r =
+    [99.99, 99.99, 99.99, 1.0,
+     1.0,   2.0,   2.0,   2.0,
+     2.0,   3.0,   4.0,   4.0,
+     4.0,   0.0,   0.0,   0.0]
+
+utils_t1 :: [Double]
+utils_t1 = take 16 $ embed (dHold 99.99) utils_inp2
+
+utils_t1r =
+    [99.99, 1.0, 1.0, 1.0,
+     1.0,   2.0, 2.0, 2.0,
+     2.0,   3.0, 4.0, 4.0,
+     4.0,   0.0, 0.0, 0.0]
+
+
+utils_inp3 = deltaEncode 1.0 $
+    [Nothing,  Nothing,  Just 1.0, Just 2.0, Just 3.0,
+     Just 4.0, Nothing,  Nothing,  Nothing,  Just 3.0,
+     Just 2.0, Nothing,  Just 1.0, Just 0.0, Just 1.0,
+     Just 2.0, Just 3.0, Nothing,  Nothing,  Just 4.0]
+    ++ repeat Nothing
+
+utils_inp4 = deltaEncode 1.0 $
+    [Just 0.0, Nothing,  Just 1.0, Just 2.0, Just 3.0,
+     Just 4.0, Nothing,  Nothing,  Nothing,  Just 3.0,
+     Just 2.0, Nothing,  Just 1.0, Just 0.0, Just 1.0,
+     Just 2.0, Just 3.0, Nothing,  Nothing,  Just 4.0]
+    ++ repeat Nothing
+
+
+utils_t2 :: [Double]
+utils_t2 = take 25 $ embed (dTrackAndHold 99.99) utils_inp3
+
+utils_t2r =
+    [99.99, 99.99, 99.99, 1.0, 2.0,
+     3.0,   4.0,   4.0,   4.0, 4.0,
+     3.0,   2.0,   2.0,   1.0, 0.0,
+     1.0,   2.0,   3.0,   3.0, 3.0,
+     4.0,   4.0,   4.0,   4.0, 4.0]
+
+utils_t3 :: [Double]
+utils_t3 = take 25 $ embed (dTrackAndHold 99.99) utils_inp4
+
+utils_t3r =
+    [99.99, 0.0, 0.0, 1.0, 2.0,
+     3.0,   4.0, 4.0, 4.0, 4.0,
+     3.0,   2.0, 2.0, 1.0, 0.0,
+     1.0,   2.0, 3.0, 3.0, 3.0,
+     4.0,   4.0, 4.0, 4.0, 4.0]
+
+
+utils_t4 :: [Event Int]
+utils_t4 = take 16 $ embed count utils_inp1
+
+utils_t4r :: [Event Int]
+utils_t4r =
+    [NoEvent, NoEvent, Event 1, NoEvent,
+     Event 2, NoEvent, NoEvent, NoEvent,
+     Event 3, Event 4, Event 5, NoEvent,
+     Event 6, NoEvent, NoEvent, NoEvent]
+
+
+utils_t5 :: [Event Int]
+utils_t5 = take 16 $ embed count utils_inp2
+
+utils_t5r :: [Event Int]
+utils_t5r =
+    [Event 1, NoEvent, NoEvent, NoEvent,
+     Event 2, NoEvent, NoEvent, NoEvent,
+     Event 3, Event 4, Event 5, NoEvent,
+     Event 6, NoEvent, NoEvent, NoEvent]
+
+
+dynDelayLine :: a -> SF (a, Event Bool) a
+dynDelayLine a0 =
+    second (arr (fmap (\p -> if p then addDelay else delDelay)))
+    >>> loop (arr (\((a, e), as) -> (a:as, e))
+              >>> rpSwitchZ [iPre a0]
+              >>> arr (\as -> (last as, init as)))
+    where
+	addDelay ds = ds ++ [last ds]
+
+        delDelay [d] = [d]
+        delDelay ds  = init ds
+
+utils_t6 :: [Int]
+utils_t6 = take 200 $ embed (dynDelayLine 0)
+			    (deltaEncode 0.1 (zip [1..] evSeq))
+    where
+	evSeq = NoEvent : Event True : NoEvent : NoEvent : Event True :
+		NoEvent : NoEvent : Event False : evSeq
+
+utils_t6r =
+    [0,1,1,2,3,3,4,6,7,8,8,9,10,10,11,13,14,15,15,16,17,17,18,20,21,22,22,23,
+     24,24,25,27,28,29,29,30,31,31,32,34,35,36,36,37,38,38,39,41,42,43,43,44,
+     45,45,46,48,49,50,50,51,52,52,53,55,56,57,57,58,59,59,60,62,63,64,64,65,
+     66,66,67,69,70,71,71,72,73,73,74,76,77,78,78,79,80,80,81,83,84,85,85,86,
+     87,87,88,90,91,92,92,93,94,94,95,97,98,99,99,100,101,101,102,104,105,106,
+     106,107,108,108,109,111,112,113,113,114,115,115,116,118,119,120,120,121,
+     122,122,123,125,126,127,127,128,129,129,130,132,133,134,134,135,136,136,
+     137,139,140,141,141,142,143,143,144,146,147,148,148,149,150,150,151,153,
+     154,155,155,156,157,157,158,160,161,162,162,163,164,164,165,167,168,169,
+     169,170,171,171,172,174]
+
+utils_t7 :: [Double]
+utils_t7 = take 50 $ embed impulseIntegral
+                           (deltaEncode 0.1 (zip (repeat 1.0) evSeq))
+    where
+	evSeq = replicate 9 NoEvent ++ [Event 10.0]
+		++ replicate 9 NoEvent ++ [Event (-10.0)]
+		++ evSeq
+
+utils_t7r =
+    [ 0.0,  0.1,  0.2,  0.3,  0.4,  0.5,  0.6,  0.7,  0.8, 10.9,
+     11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8,  1.9,
+      2.0,  2.1,  2.2,  2.3,  2.4,  2.5,  2.6,  2.7,  2.8, 12.9,
+     13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8,  3.9,
+      4.0,  4.1,  4.2,  4.3,  4.4,  4.5,  4.6,  4.7,  4.8, 14.9]
+
+
+utils_t8 :: [Double]
+utils_t8 = take 50 $ embed (provided (even . floor) integral (constant (-1)))
+                           (deltaEncode 0.1 input)
+    where
+	input = replicate 10 1
+		++ replicate 10 2
+		++ replicate 10 3
+		++ replicate 10 4
+		++ input
+
+utils_t8r =
+    [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0,
+      0.0,  0.2,  0.4,  0.6,  0.8,  1.0,  1.2,  1.4,  1.6,  1.8,
+     -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0,
+      0.0,  0.4,  0.8,  1.2,  1.6,  2.0,  2.4,  2.8,  3.2,  3.6,
+     -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0]
+
+
+utils_t9 :: [Double]
+utils_t9 = take 50 $ embed (provided (odd . floor) integral (constant (-1)))
+                           (deltaEncode 0.1 input)
+    where
+	input = replicate 10 1
+		++ replicate 10 2
+		++ replicate 10 3
+		++ replicate 10 4
+		++ input
+
+utils_t9r =
+    [ 0.0,  0.1,  0.2,  0.3,  0.4,  0.5,  0.6,  0.7,  0.8,  0.9,
+     -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0,
+      0.0,  0.3,  0.6,  0.9,  1.2,  1.5,  1.8,  2.1,  2.4,  2.7,
+     -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0,
+      0.0,  0.1,  0.2,  0.3,  0.4,  0.5,  0.6,  0.7,  0.8,  0.9]
+
+
+utils_t10 :: [Event Double]
+utils_t10 = testSF1 snap
+
+utils_t10r =
+    [Event 0.0, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent,   NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent,   NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     NoEvent,   NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent,   NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent,   NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+utils_t11 :: [Event Double]
+utils_t11 = testSF1 (snapAfter 2.6)
+
+utils_t11r =
+    [NoEvent, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent, Event 11.0,	-- 2.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+
+utils_t12 :: [Event Double]
+utils_t12 = testSF1 (sample 0.99)
+
+utils_t12r =
+    [NoEvent,    NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     Event 4.0,  NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     Event 8.0,  NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     Event 12.0, NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     Event 16.0, NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     Event 20.0, NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     Event 24.0]
+
+
+utils_t13 :: [Event ()]
+utils_t13 = testSF1 (recur (after 0.99 ()))
+
+utils_t13r =
+    [NoEvent,  NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     Event (), NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     Event (), NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     Event (), NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     Event (), NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     Event (), NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     Event ()]
+
+
+utils_t14 :: [Event Int]
+utils_t14 = testSF1 (after 1.0 1 `andThen` now 2 `andThen` after 2.0 3)
+
+utils_t14r =
+    [NoEvent, NoEvent, NoEvent, NoEvent,	-- 0.0 s
+     Event 1, NoEvent, NoEvent, NoEvent,	-- 1.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 2.0 s
+     Event 3, NoEvent, NoEvent, NoEvent,	-- 3.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 4.0 s
+     NoEvent, NoEvent, NoEvent, NoEvent,	-- 5.0 s
+     NoEvent]
+
+utils_t15 = take 50 (embed (time >>> sampleWindow 5 0.5)
+                           (deltaEncode 0.125 (repeat ())))
+
+utils_t15r =
+    [ NoEvent,                     NoEvent, NoEvent, NoEvent,	-- 0.0 s
+      Event [0.5],                 NoEvent, NoEvent, NoEvent,	-- 0.5 s
+      Event [0.5,1.0],             NoEvent, NoEvent, NoEvent,	-- 1.0 s
+      Event [0.5,1.0,1.5],         NoEvent, NoEvent, NoEvent,	-- 1.5 s
+      Event [0.5,1.0,1.5,2.0],     NoEvent, NoEvent, NoEvent, 	-- 2.0 s
+      Event [0.5,1.0,1.5,2.0,2.5], NoEvent, NoEvent, NoEvent,	-- 2.5 s
+      Event [1.0,1.5,2.0,2.5,3.0], NoEvent, NoEvent, NoEvent,	-- 3.0 s
+      Event [1.5,2.0,2.5,3.0,3.5], NoEvent, NoEvent, NoEvent,	-- 3.5 s
+      Event [2.0,2.5,3.0,3.5,4.0], NoEvent, NoEvent, NoEvent,	-- 4.0 s
+      Event [2.5,3.0,3.5,4.0,4.5], NoEvent, NoEvent, NoEvent,	-- 4.5 s
+      Event [3.0,3.5,4.0,4.5,5.0], NoEvent, NoEvent, NoEvent,	-- 5.0 s
+      Event [3.5,4.0,4.5,5.0,5.5], NoEvent, NoEvent, NoEvent,	-- 5.5 s
+      Event [4.0,4.5,5.0,5.5,6.0], NoEvent			-- 6.0 s
+    ]
+
+
+{-
+-- Not robust
+utils_t16 = take 50 (embed (time >>> sampleWindow 5 0.5) input)
+    where
+        input = ((), [(dt, Just ()) | dt <- dts])
+
+        dts = replicate 15 0.1
+              ++ [1.0, 1.0]
+              ++ replicate 15 0.1
+              ++ [2.0]
+              ++ replicate 10 0.1
+
+utils_t16r =
+    [ NoEvent, NoEvent,          NoEvent, NoEvent, NoEvent,		-- 0.0
+      NoEvent, Event [0.6],      NoEvent, NoEvent, NoEvent,		-- 0.5
+      NoEvent, Event [0.6, 1.1], NoEvent, NoEvent, NoEvent,		-- 1.0
+      NoEvent,								-- 1.5
+      Event [0.6,1.1,2.5,2.5,2.5],               			-- 2.5
+      Event [2.5,2.5,2.5,3.5,3.5], NoEvent, NoEvent, NoEvent, NoEvent,	-- 3.5
+      NoEvent, Event [2.5,2.5,3.5,3.5,4.1], NoEvent, NoEvent, NoEvent,  -- 4.0
+      NoEvent, Event [2.5,3.5,3.5,4.1,4.6], NoEvent, NoEvent, NoEvent,	-- 4.5
+      NoEvent,								-- 5.0
+      Event [7.0,7.0,7.0,7.0,7.0], NoEvent, NoEvent, NoEvent, NoEvent,	-- 7.0
+      NoEvent, Event [7.0,7.0,7.0,7.0,7.6], NoEvent, NoEvent, NoEvent,	-- 7.5
+      NoEvent								-- 8.0
+    ]
+-}
+
+utils_t16 = take 50 (embed (time >>> sampleWindow 5 0.4999) input)
+    where
+        input = ((), [(dt, Just ()) | dt <- dts])
+
+        dts = replicate 15 0.1
+              ++ [1.0, 1.0]
+              ++ replicate 15 0.1
+              ++ [2.0]
+              ++ replicate 10 0.1
+
+utils_t16r =
+    [ NoEvent,          NoEvent, NoEvent, NoEvent, NoEvent,		-- 0.0
+      Event [0.5],      NoEvent, NoEvent, NoEvent, NoEvent,		-- 0.5
+      Event [0.5, 1.0], NoEvent, NoEvent, NoEvent, NoEvent,		-- 1.0
+      Event [0.5, 1.0, 1.5],						-- 1.5
+      Event [0.5, 1.0, 1.5, 2.5, 2.5],         				-- 2.5
+      Event [1.5, 2.5, 2.5, 3.5, 3.5], NoEvent, NoEvent, NoEvent,	-- 3.5
+                                                         NoEvent,
+      Event [2.5, 2.5, 3.5, 3.5, 4.0], NoEvent, NoEvent, NoEvent,  	-- 4.0
+      							 NoEvent,
+      Event [2.5, 3.5, 3.5, 4.0, 4.5], NoEvent, NoEvent, NoEvent,	-- 4.5
+							 NoEvent,
+      Event [3.5, 3.5, 4.0, 4.5, 5.0],					-- 5.0
+      Event [5.0, 7.0, 7.0, 7.0, 7.0], NoEvent, NoEvent, NoEvent,	-- 7.0
+							 NoEvent,
+      Event [7.0, 7.0, 7.0, 7.0, 7.5], NoEvent, NoEvent, NoEvent,	-- 7.5
+							 NoEvent,
+      Event [7.0, 7.0, 7.0, 7.5, 8.0]					-- 8.0
+    ]
+
+utils_trs =
+    [ utils_t0 ~= utils_t0r,
+      utils_t1 ~= utils_t1r,
+      utils_t2 ~= utils_t2r,
+      utils_t3 ~= utils_t3r,
+      utils_t4 ~= utils_t4r,
+      utils_t5 ~= utils_t5r,
+      utils_t6 ~= utils_t6r,
+      utils_t7 ~= utils_t7r,
+      utils_t8 ~= utils_t8r,
+      utils_t9 ~= utils_t9r,
+      utils_t10 ~= utils_t10r,
+      utils_t11 ~= utils_t11r,
+      utils_t12 ~= utils_t12r,
+      utils_t13 ~= utils_t13r,
+      utils_t14 ~= utils_t14r,
+      utils_t15 ~= utils_t15r,
+      utils_t16 ~= utils_t16r
+    ]
+
+utils_tr = and utils_trs
diff --git a/tests/TestsWFG.hs b/tests/TestsWFG.hs
new file mode 100644
--- /dev/null
+++ b/tests/TestsWFG.hs
@@ -0,0 +1,103 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: TestsWFG.hs,v 1.2 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         TestsWFG					         *
+*       Purpose:        Test cases for wave-form generation		     *
+*	Authors:	Antony Courtney and Henrik Nilsson		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+
+module TestsWFG (wfg_tr, wfg_trs) where
+
+import FRP.Yampa
+
+import TestsCommon
+
+------------------------------------------------------------------------------
+-- Test cases for wave-form generation
+------------------------------------------------------------------------------
+
+wfg_inp1 = deltaEncode 1.0 $
+    [NoEvent,   NoEvent,   Event 1.0, NoEvent,
+     Event 2.0, NoEvent,   NoEvent,   NoEvent,
+     Event 3.0, Event 4.0, Event 4.0, NoEvent,
+     Event 0.0, NoEvent,   NoEvent,   NoEvent]
+    ++ repeat NoEvent
+
+
+wfg_inp2 = deltaEncode 1.0 $
+    [Event 1.0, NoEvent,   NoEvent,   NoEvent,
+     Event 2.0, NoEvent,   NoEvent,   NoEvent,
+     Event 3.0, Event 4.0, Event 4.0, NoEvent,
+     Event 0.0, NoEvent,   NoEvent,   NoEvent]
+    ++ repeat NoEvent
+
+
+wfg_t0 :: [Double]
+wfg_t0 = take 16 $ embed (hold 99.99) wfg_inp1
+
+wfg_t0r =
+    [99.99, 99.99, 1.0, 1.0,
+     2.0,   2.0,   2.0, 2.0,
+     3.0,   4.0,   4.0, 4.0,
+     0.0,   0.0,   0.0, 0.0]
+
+wfg_t1 :: [Double]
+wfg_t1 = take 16 $ embed (hold 99.99) wfg_inp2
+
+wfg_t1r =
+    [1.0, 1.0, 1.0, 1.0,
+     2.0, 2.0, 2.0, 2.0,
+     3.0, 4.0, 4.0, 4.0,
+     0.0, 0.0, 0.0, 0.0]
+
+wfg_inp3 = deltaEncode 1.0 $
+    [Nothing,  Nothing,  Just 1.0, Just 2.0, Just 3.0,
+     Just 4.0, Nothing,  Nothing,  Nothing,  Just 3.0,
+     Just 2.0, Nothing,  Just 1.0, Just 0.0, Just 1.0,
+     Just 2.0, Just 3.0, Nothing,  Nothing,  Just 4.0]
+    ++ repeat Nothing
+
+wfg_inp4 = deltaEncode 1.0 $
+    [Just 0.0, Nothing,  Just 1.0, Just 2.0, Just 3.0,
+     Just 4.0, Nothing,  Nothing,  Nothing,  Just 3.0,
+     Just 2.0, Nothing,  Just 1.0, Just 0.0, Just 1.0,
+     Just 2.0, Just 3.0, Nothing,  Nothing,  Just 4.0]
+    ++ repeat Nothing
+
+
+wfg_t2 :: [Double]
+wfg_t2 = take 25 $ embed (trackAndHold 99.99) wfg_inp3
+
+wfg_t2r =
+    [99.99, 99.99, 1.0, 2.0, 3.0,
+     4.0,   4.0,   4.0, 4.0, 3.0,
+     2.0,   2.0,   1.0, 0.0, 1.0,
+     2.0,   3.0,   3.0, 3.0, 4.0,
+     4.0,   4.0,   4.0, 4.0, 4.0]
+
+
+wfg_t3 :: [Double]
+wfg_t3 = take 25 $ embed (trackAndHold 99.99) wfg_inp4
+
+wfg_t3r =
+    [0.0, 0.0, 1.0, 2.0, 3.0,
+     4.0, 4.0, 4.0, 4.0, 3.0,
+     2.0, 2.0, 1.0, 0.0, 1.0,
+     2.0, 3.0, 3.0, 3.0, 4.0,
+     4.0, 4.0, 4.0, 4.0, 4.0]
+
+
+wfg_trs =
+    [ wfg_t0 ~= wfg_t0r,
+      wfg_t1 ~= wfg_t1r,
+      wfg_t2 ~= wfg_t2r,
+      wfg_t3 ~= wfg_t3r
+    ]
+
+wfg_tr = and wfg_trs
diff --git a/tests/YampaQC.hs b/tests/YampaQC.hs
--- a/tests/YampaQC.hs
+++ b/tests/YampaQC.hs
@@ -36,8 +36,7 @@
 
 tests :: TestTree
 tests = testGroup "Yampa QC properties"
-    [ testProperty "SF based on (**2) equal to SF on (^2))" prop_arr_law1
-    , testProperty "Identity"                               prop_arr_id
+    [ testProperty "Identity"                               prop_arr_id
     , testProperty "Arrow Naturality"                       prop_arr_naturality
     , testProperty "Naturality"                             prop_arr_naturality
     , testProperty "Basic > Identity (1)"                   prop_basic_identity_1
@@ -95,10 +94,6 @@
 -- * Yampa laws
 
 -- ** Arrow laws
-prop_arr_law1 =
-   forAll myStream (evalT $ prop_always_equal (arr (**2)) (arr (^2)))
- where myStream :: Gen (SignalSampleStream Float)
-       myStream = uniDistStream
 
 prop_arr_id =
    forAll myStream (evalT $ prop_always_equal (arr id) identity)
diff --git a/tests/testYampaMain.hs b/tests/testYampaMain.hs
new file mode 100644
--- /dev/null
+++ b/tests/testYampaMain.hs
@@ -0,0 +1,78 @@
+{-# OPTIONS_GHC -fno-warn-tabs #-}
+{- $Id: testYampaMain.hs,v 1.9 2003/11/10 21:28:58 antony Exp $
+******************************************************************************
+*                                  Y A M P A                                 *
+*                                                                            *
+*       Module:         testYampaMain                                        *
+*       Purpose:        Main driver routine for running tests.               *
+*	Authors:	Henrik Nilsson and Antony Courtney		     *
+*                                                                            *
+*             Copyright (c) Yale University, 2003                            *
+*                                                                            *
+******************************************************************************
+-}
+module Main where
+
+import Tests
+
+import Control.Monad (when)
+import System.Environment (getArgs, getProgName)
+import System.Exit (exitWith, ExitCode(..))
+import System.IO
+
+-- main = runTests
+-- main = runSpaceTests
+
+data TestFlags = TestFlags { tReg :: Bool -- run regression tests
+			   , tSpace :: Bool -- run space tests
+			   , tHelp :: Bool -- print usage and exit
+			     }
+
+defFlags = TestFlags { tReg = False, tSpace = False, tHelp = False}
+allFlags = TestFlags { tReg = True, tSpace = True, tHelp = False}
+
+parseArgs :: TestFlags -> [String] -> Either TestFlags String
+parseArgs flags [] = Left flags
+parseArgs flags (arg:args) =
+  case arg of
+    "-r" -> parseArgs (flags {tReg = True}) args
+    "-s" -> parseArgs (flags {tSpace = True}) args
+    "-h" -> parseArgs (flags {tHelp = True}) args
+    _ -> Right ("invalid argument: " ++ arg)
+
+usage :: String -> Maybe String -> IO ()
+usage pname mbEmsg = do
+  case mbEmsg of
+    (Just emsg) -> hPutStrLn stderr (pname ++ ": " ++ emsg)
+    _ -> return ()
+  hPutStrLn stderr ("usage: " ++ pname ++ " [-r] [-s] [-h]")
+  hPutStrLn stderr "\t-s run space tests"
+  hPutStrLn stderr "\t-r run regression tests"
+  hPutStrLn stderr "\t-h print this help message"
+  hPutStrLn stderr "(no arguments runs all tests.)"
+
+main :: IO ()
+main = do
+  pname <- getProgName
+  args <- getArgs
+  let eFlags = if (length args) < 1
+                 then Left allFlags
+                 else parseArgs defFlags args
+  case eFlags of
+    Right emsg  -> usage pname (Just emsg)
+    Left tFlags ->
+      if tHelp tFlags
+        then usage pname Nothing
+        else do
+          -- Run regresion tests, check if passed
+          t <- if tReg tFlags
+                 then runRegTests
+                 else return True
+          -- Run space tests
+          when (tSpace tFlags)
+                  runSpaceTests
+          -- Communicate if all tests have passed
+          let exitCode = if t then ExitSuccess else (ExitFailure 1)
+          exitWith exitCode
+
+
diff --git a/yampa-test.cabal b/yampa-test.cabal
--- a/yampa-test.cabal
+++ b/yampa-test.cabal
@@ -1,6 +1,45 @@
-name:                yampa-test
-version:             0.13.3
-synopsis:            Testing library for Yampa.
+-- Copyright (c) 2017, Ivan Perez
+--
+-- All rights reserved.
+--
+-- Redistribution and use in source and binary forms, with or without
+-- modification, are permitted provided that the following conditions are met:
+--
+--     * Redistributions of source code must retain the above copyright notice,
+--       this list of conditions and the following disclaimer.
+--
+--     * Redistributions in binary form must reproduce the above copyright
+--       notice, this list of conditions and the following disclaimer in the
+--       documentation and/or other materials provided with the distribution.
+--
+--     * Neither the name of Ivan Perez nor the names of other contributors may
+--       be used to endorse or promote products derived from this software
+--       without specific prior written permission.
+--
+-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+-- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+-- POSSIBILITY OF SUCH DAMAGE.
+cabal-version: >= 1.10
+build-type:    Simple
+
+name:          yampa-test
+version:       0.13.4
+author:        Ivan Perez
+maintainer:    ivan.perez@keera.co.uk
+homepage:      http://github.com/ivanperez-keera/Yampa
+license:       BSD3
+license-file:  LICENSE
+-- copyright
+category:      Testing
+synopsis:      Testing library for Yampa.
 description:
   Testing and debugging library for Yampa.
   .
@@ -15,44 +54,118 @@
   A detailed explanation of these ideas is included in the ICFP 2017 paper
   <https://dl.acm.org/citation.cfm?id=3110246 Testing and Debugging Functional Reactive Programming>.
 
-homepage:            http://github.com/ivanperez-keera/Yampa
-license:             BSD3
-license-file:        LICENSE
-author:              Ivan Perez
-maintainer:          ivan.perez@keera.co.uk
--- copyright:
-category:            Testing
-build-type:          Simple
-extra-source-files:  CHANGELOG
+extra-source-files:
+  CHANGELOG
 
-cabal-version:       >=1.10
 
+source-repository head
+  type:     git
+  location: git://github.com/ivanperez-keera/Yampa.git
+  subdir:   yampa-test
+
+
+-- You can disable the regression test suite with -f-test-regression
+flag test-regression
+  description: Enable regression test suite
+  default:     True
+  manual:      True
+
+
 library
-  exposed-modules:     FRP.Yampa.Debug
-                       FRP.Yampa.LTLFuture
-                       FRP.Yampa.LTLPast
-                       FRP.Yampa.Stream
-                       FRP.Yampa.QuickCheck
-  build-depends:       base >=4 && <5,
-                       Yampa >= 0.13.3 && < 0.14,
-                       QuickCheck,
-                       normaldistribution
-  hs-source-dirs:      src
-  default-language:    Haskell2010
+  exposed-modules:
+    FRP.Yampa.Debug
+    FRP.Yampa.LTLFuture
+    FRP.Yampa.LTLPast
+    FRP.Yampa.QuickCheck
+    FRP.Yampa.Stream
 
+  build-depends:
+      base               >= 4      && < 5
+    , normaldistribution
+    , QuickCheck
+    , Yampa              >= 0.13.4 && < 0.14
+
+  default-language:
+    Haskell2010
+
+  hs-source-dirs:
+    src
+
+
 test-suite yampa-quicheck
-  type:        exitcode-stdio-1.0
-  main-is:     YampaQC.hs
-  ghc-options: -Wall
-  default-language:    Haskell2010
+  type:
+    exitcode-stdio-1.0
 
-  hs-source-dirs:   tests
+  main-is:
+    YampaQC.hs
+
   build-depends:
-    base < 5,
-    random,
-    Cabal >= 1.19,
-    QuickCheck,
-    tasty,
-    tasty-quickcheck,
-    Yampa,
-    yampa-test
+      base             < 5
+    , Cabal            >= 1.19
+    , QuickCheck
+    , random
+    , tasty
+    , tasty-quickcheck
+    , Yampa
+    , yampa-test
+
+  default-language:
+    Haskell2010
+
+  hs-source-dirs:
+    tests
+
+  ghc-options:
+    -Wall
+
+
+test-suite regression
+  type:
+    exitcode-stdio-1.0
+
+  main-is:
+    testYampaMain.hs
+
+  other-modules:
+    Tests
+    TestsAccum
+    TestsArr
+    TestsBasicSF
+    TestsCOC
+    TestsCommon
+    TestsComp
+    TestsDelay
+    TestsDer
+    TestsEmbed
+    TestsEvSrc
+    TestsFirstSecond
+    TestsKSwitch
+    TestsLaws
+    TestsLoop
+    TestsLoopIntegral
+    TestsLoopLaws
+    TestsLoopPre
+    TestsPre
+    TestsPSwitch
+    TestsReact
+    TestsRPSwitch
+    TestsRSwitch
+    TestsSscan
+    TestsSwitch
+    TestsTask
+    TestsUtils
+    TestsWFG
+
+  default-language:
+    Haskell2010
+
+  hs-source-dirs:
+    tests
+
+  if !flag(test-regression)
+    buildable:
+      False
+  else
+    build-depends:
+        base
+      , Yampa
