diff --git a/hmatrix-tests.cabal b/hmatrix-tests.cabal
--- a/hmatrix-tests.cabal
+++ b/hmatrix-tests.cabal
@@ -1,5 +1,5 @@
 Name:               hmatrix-tests
-Version:            0.6.0.0
+Version:            0.19.0.0
 License:            BSD3
 License-file:       LICENSE
 Author:             Alberto Ruiz
diff --git a/src/Numeric/GSL/Tests.hs b/src/Numeric/GSL/Tests.hs
--- a/src/Numeric/GSL/Tests.hs
+++ b/src/Numeric/GSL/Tests.hs
@@ -1,4 +1,4 @@
-{-# OPTIONS_GHC -fno-warn-unused-imports -fno-warn-incomplete-patterns #-}
+{-# OPTIONS_GHC -fno-warn-unused-imports -fno-warn-incomplete-patterns -fno-warn-missing-signatures #-}
 {- |
 Module      :  Numeric.GLS.Tests
 Copyright   :  (c) Alberto Ruiz 2014
diff --git a/src/Numeric/LinearAlgebra/Tests.hs b/src/Numeric/LinearAlgebra/Tests.hs
--- a/src/Numeric/LinearAlgebra/Tests.hs
+++ b/src/Numeric/LinearAlgebra/Tests.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE CPP #-}
-{-# OPTIONS_GHC -fno-warn-unused-imports -fno-warn-incomplete-patterns #-}
+{-# OPTIONS_GHC -fno-warn-unused-imports -fno-warn-incomplete-patterns -fno-warn-missing-signatures #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE FlexibleContexts #-}
@@ -31,7 +31,7 @@
 --, runBigTests
 ) where
 
-import Numeric.LinearAlgebra hiding (unitary)
+import Numeric.LinearAlgebra
 import Numeric.LinearAlgebra.Devel
 import Numeric.LinearAlgebra.Static(L)
 import Numeric.LinearAlgebra.Tests.Instances
@@ -39,7 +39,11 @@
 import Test.HUnit hiding ((~:),test,Testable,State)
 import System.Info
 import Data.List(foldl1')
+#if MIN_VERSION_base(4,11,0)
+import Prelude hiding ((^),(<>))
+#else
 import Prelude hiding ((^))
+#endif
 import qualified Prelude
 import System.CPUTime
 import System.Exit
@@ -131,6 +135,111 @@
     ok1 = mbChol (trustSym m1) == Nothing
     ok2 = mbChol (trustSym m2) == Just (chol $ trustSym m2)
 
+-----------------------------------------------------
+
+triTest = utest "triTest" ok1 where
+
+  a :: Matrix R
+  a = (4><4)
+    [
+       4.30,  0.00,  0.00, 0.00,
+      -3.96, -4.87,  0.00, 0.00,
+       0.40,  0.31, -8.02, 0.00,
+      -0.27,  0.07, -5.95, 0.12
+    ]
+
+  w :: Matrix R
+  w = (4><2)
+    [
+      -12.90, -21.50,
+       16.75,  14.93,
+      -17.55,   6.33,
+      -11.04,   8.09
+    ]
+
+  v :: Matrix R
+  v = triSolve Lower a w
+
+  e :: Matrix R
+  e = (4><2)
+    [
+      -3.0000, -5.0000,
+      -1.0000,  1.0000,
+       2.0000, -1.0000,
+       1.0000,  6.0000
+    ]
+
+  ok1 = (norm_Inf . flatten $ e - v) <= 1e-13
+
+-----------------------------------------------------
+
+triDiagTest = utest "triDiagTest" (ok1 && ok2) where
+
+  dL, d, dU :: Vector Double
+  dL =  fromList [3.0, 3.0, 3.0, 3.0, 3.0, 3.0, 3.0, 3.0]
+  d  =  fromList [1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0]
+  dU =  fromList [4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0]
+
+  b :: Matrix R
+  b = (9><3)
+    [
+      1.0,   1.0,   1.0,
+      1.0,  -1.0,   2.0,
+      1.0,   1.0,   3.0,
+      1.0,  -1.0,   4.0,
+      1.0,   1.0,   5.0,
+      1.0,  -1.0,   6.0,
+      1.0,   1.0,   7.0,
+      1.0,  -1.0,   8.0,
+      1.0,   1.0,   9.0
+    ]
+
+  y :: Matrix R
+  y = (9><9)
+    [
+      1.0, 4.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+      3.0, 1.0, 4.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+      0.0, 3.0, 1.0, 4.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+      0.0, 0.0, 3.0, 1.0, 4.0, 0.0, 0.0, 0.0, 0.0,
+      0.0, 0.0, 0.0, 3.0, 1.0, 4.0, 0.0, 0.0, 0.0,
+      0.0, 0.0, 0.0, 0.0, 3.0, 1.0, 4.0, 0.0, 0.0,
+      0.0, 0.0, 0.0, 0.0, 0.0, 3.0, 1.0, 4.0, 0.0,
+      0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 3.0, 1.0, 4.0,
+      0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 3.0, 1.0
+    ]
+
+  x :: Matrix R
+  x = triDiagSolve dL d dU b
+
+  z :: Matrix C
+  z = (4><4)
+    [
+      1.0 :+ 1.0, 4.0 :+ 4.0, 0.0 :+ 0.0, 0.0 :+ 0.0,
+      3.0 :+ 3.0, 1.0 :+ 1.0, 4.0 :+ 4.0, 0.0 :+ 0.0,
+      0.0 :+ 0.0, 3.0 :+ 3.0, 1.0 :+ 1.0, 4.0 :+ 4.0,
+      0.0 :+ 0.0, 0.0 :+ 0.0, 3.0 :+ 3.0, 1.0 :+ 1.0
+    ]
+
+  zDL, zD, zDu :: Vector C
+  zDL = fromList [3.0 :+ 3.0, 3.0 :+ 3.0, 3.0 :+ 3.0]
+  zD  = fromList [1.0 :+ 1.0, 1.0 :+ 1.0, 1.0 :+ 1.0, 1.0 :+ 1.0]
+  zDu = fromList [4.0 :+ 4.0, 4.0 :+ 4.0, 4.0 :+ 4.0]
+
+  zB :: Matrix C
+  zB = (4><3)
+    [
+      1.0 :+ 1.0,   1.0  :+   1.0,  1.0 :+ (-1.0),
+      1.0 :+ 1.0, (-1.0) :+ (-1.0), 1.0 :+ (-1.0),
+      1.0 :+ 1.0,   1.0  :+   1.0,  1.0 :+ (-1.0),
+      1.0 :+ 1.0, (-1.0) :+ (-1.0), 1.0 :+ (-1.0)
+    ]
+
+  u :: Matrix C
+  u = triDiagSolve zDL zD zDu zB
+
+  ok1 = (maximum $ map abs $ concat $ toLists $ b - (y <> x)) <= 1e-15
+  ok2 = (maximum $ map magnitude $ concat $ toLists $ zB - (z <> u)) <= 1e-15
+
 ---------------------------------------------------------------------
 
 randomTestGaussian = (unSym c) :~3~: unSym (snd (meanCov dat))
@@ -405,7 +514,7 @@
 
 --------------------------------------------------------------------------------
 
-sliceTest = utest "slice test" $ and
+_sliceTest = TestList
     [ testSlice (chol . trustSym)  (gen 5 :: Matrix R)
     , testSlice (chol . trustSym)  (gen 5 :: Matrix C)
     , testSlice qr    (rec :: Matrix R)
@@ -508,7 +617,7 @@
 
     test_qrgr n t x = qrgr n (QR x t)
 
-    ok_qrgr x = simeq 1E-15 q q'
+    ok_qrgr x = TestCase . assertBool "ok_qrgr" $ simeq 1E-15 q q'
       where
         (q,_) = qr x
         atau = qrRaw x
@@ -537,7 +646,8 @@
     rec :: Numeric t => Matrix t
     rec = subMatrix (0,0) (4,5) (gen 5)
 
-    testSlice f x@(size->sz@(r,c)) = all (==f x) (map f (g y1 ++ g y2))
+    testSlice f x@(size->sz@(r,c)) =
+      TestList . map (TestCase . assertEqual "" (f x)) $ (map f (g y1 ++ g y2))
       where
         subm = subMatrix
         g y = [ subm (a*r,b*c) sz y | a <-[0..2], b <- [0..2]]
@@ -715,6 +825,8 @@
                        && rank ((2><3)[1,0,0,1,7*peps,0::Double]) == 2
         , utest "block" $ fromBlocks [[ident 3,0],[0,ident 4]] == (ident 7 :: CM)
         , mbCholTest
+        , triTest
+        , triDiagTest
         , utest "offset" offsetTest
         , normsVTest
         , normsMTest
@@ -730,7 +842,7 @@
         , staticTest
         , intTest
         , modularTest
-        , sliceTest
+        -- , sliceTest
         ]
     when (errors c + failures c > 0) exitFailure
     return ()
diff --git a/src/Numeric/LinearAlgebra/Tests/Instances.hs b/src/Numeric/LinearAlgebra/Tests/Instances.hs
--- a/src/Numeric/LinearAlgebra/Tests/Instances.hs
+++ b/src/Numeric/LinearAlgebra/Tests/Instances.hs
@@ -1,4 +1,8 @@
-{-# LANGUAGE FlexibleContexts, UndecidableInstances, FlexibleInstances, ScopedTypeVariables #-}
+{-# LANGUAGE CPP, FlexibleContexts, UndecidableInstances, FlexibleInstances, ScopedTypeVariables #-}
+
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+{-# OPTIONS_GHC -fno-warn-missing-signatures #-}
+
 -----------------------------------------------------------------------------
 {- |
 Module      :  Numeric.LinearAlgebra.Tests.Instances
@@ -32,7 +36,9 @@
 import GHC.TypeLits
 import Data.Proxy (Proxy(..))
 import qualified Numeric.LinearAlgebra.Static as Static
-
+#if MIN_VERSION_base(4,11,0)
+import Prelude hiding ((<>))
+#endif
 
 shrinkListElementwise :: (Arbitrary a) => [a] -> [[a]]
 shrinkListElementwise []     = []
@@ -60,7 +66,7 @@
         n :: Int
         n = fromIntegral (natVal (Proxy :: Proxy n))
 
-    shrink v = []
+    shrink _v = []
 
 instance (Element a, Arbitrary a) => Arbitrary (Matrix a) where
     arbitrary = do
@@ -87,7 +93,7 @@
         n :: Int
         n = fromIntegral (natVal (Proxy :: Proxy n))
 
-    shrink mat = []
+    shrink _mat = []
 
 -- a square matrix
 newtype (Sq a) = Sq (Matrix a) deriving Show
diff --git a/src/Numeric/LinearAlgebra/Tests/Properties.hs b/src/Numeric/LinearAlgebra/Tests/Properties.hs
--- a/src/Numeric/LinearAlgebra/Tests/Properties.hs
+++ b/src/Numeric/LinearAlgebra/Tests/Properties.hs
@@ -1,7 +1,10 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE DataKinds #-}
 
+{-# OPTIONS_GHC -fno-warn-missing-signatures #-}
+
 -----------------------------------------------------------------------------
 {- |
 Module      :  Numeric.LinearAlgebra.Tests.Properties
@@ -50,14 +53,16 @@
   , staticVectorBinaryFailProp
 ) where
 
-import Numeric.LinearAlgebra.HMatrix hiding (Testable,unitary)
+import Numeric.LinearAlgebra.HMatrix hiding (Testable)
 import qualified Numeric.LinearAlgebra.Static as Static
 import Test.QuickCheck
 
 import Data.Binary
 import Data.Binary.Get (runGet)
 import Data.Either (isLeft)
-import Debug.Trace (traceShowId)
+#if MIN_VERSION_base(4,11,0)
+import Prelude hiding ((<>))
+#endif
 
 (~=) :: Double -> Double -> Bool
 a ~= b = abs (a - b) < 1e-10
diff --git a/src/TestBase.hs b/src/TestBase.hs
--- a/src/TestBase.hs
+++ b/src/TestBase.hs
@@ -1,3 +1,4 @@
 import Numeric.LinearAlgebra.Tests
 
+main :: IO ()
 main = runTests 20
diff --git a/src/TestGSL.hs b/src/TestGSL.hs
--- a/src/TestGSL.hs
+++ b/src/TestGSL.hs
@@ -1,3 +1,4 @@
 import Numeric.GSL.Tests
 
+main :: IO ()
 main = runTests 20