diff --git a/src/Render.hs b/src/Render.hs
--- a/src/Render.hs
+++ b/src/Render.hs
@@ -35,7 +35,8 @@
 import qualified System.IO as IO
 
 import NumericPrelude.Numeric ((*>), )
-import Prelude hiding (Real, )
+import NumericPrelude.Base
+import Prelude (Num, Float, fromInteger, )
 
 
 type Real = Float
diff --git a/src/Synthesizer/MIDI/Dimensional/Example/Instrument.hs b/src/Synthesizer/MIDI/Dimensional/Example/Instrument.hs
--- a/src/Synthesizer/MIDI/Dimensional/Example/Instrument.hs
+++ b/src/Synthesizer/MIDI/Dimensional/Example/Instrument.hs
@@ -79,7 +79,7 @@
           fmap Flat.canonicalize
             (DN.scalar end &*^ CtrlR.exponential2 (DN.time 0.1)))
       append <- CutR.append
-      return $ (DispA.inflate (DN.fromNumber $ 4**vel) (append decay release))
+      return $ DispA.inflate (DN.fromNumber $ 4**vel) (append decay release)
 --      return $ DispA.inflate (DN.fromNumber $ 4**vel) decay
 
 {-
diff --git a/synthesizer-midi.cabal b/synthesizer-midi.cabal
--- a/synthesizer-midi.cabal
+++ b/synthesizer-midi.cabal
@@ -1,5 +1,5 @@
 Name:           synthesizer-midi
-Version:        0.6.0.3
+Version:        0.6.0.4
 License:        GPL
 License-File:   LICENSE
 Author:         Henning Thielemann <haskell@henning-thielemann.de>
@@ -19,7 +19,7 @@
 Build-Type:     Simple
 
 Source-Repository this
-  Tag:         0.6.0.3
+  Tag:         0.6.0.4
   Type:        darcs
   Location:    http://code.haskell.org/synthesizer/midi/
 
@@ -34,10 +34,6 @@
   description: Build example executables
   default:     False
 
-Flag buildTests
-  description: Build test executables
-  default:     False
-
 Library
   Build-Depends:
     synthesizer-dimensional >=0.7 && <0.9,
@@ -115,19 +111,17 @@
     Default-Extensions: CPP
   Main-Is: src/Render.hs
 
-Executable test
-  If flag(buildTests)
-    Build-Depends:
-      synthesizer-midi,
-      synthesizer-core,
-      storablevector,
-      numeric-prelude,
-      midi,
-      event-list,
-      transformers,
-      base
-  Else
-    Buildable: False
+Test-Suite test
+  Type: exitcode-stdio-1.0
+  Build-Depends:
+    synthesizer-midi,
+    synthesizer-core,
+    storablevector,
+    numeric-prelude,
+    midi,
+    event-list,
+    transformers,
+    base
   Default-Language: Haskell2010
   GHC-Options: -Wall
   If impl(ghc>=7.0)