Use displayException instead of show for showing exceptions

core/CHANGELOG.md

@@ -6,10 +6,11 @@ Unreleased
 
 _YYYY-MM-DD_
 
-* Dependency loop error now lists all test cases that formed a cycle
-* `foldGroup` now takes `[b]` instead of `b` as its last argument to allow for custom fold strategies. This is a backwards incompatible change, but you can get the old behavior by applying `mconcat`.
-* Dependencies can now be defined pattern-free with `sequentialTestGroup`. (#343)
-* Added `--min-duration-to-report` flag that specifies the time a test must take before `tasty` outputs timing information ([#341](https://github.com/UnkindPartition/tasty/issues/341))
+* Dependency loop error now lists all test cases that formed a cycle ([#340](https://github.com/UnkindPartition/tasty/issues/340)).
+* `foldGroup` now takes `[b]` instead of `b` as its last argument to allow for custom fold strategies. This is a backwards incompatible change, but you can get the old behavior by applying `mconcat` ([#364](https://github.com/UnkindPartition/tasty/issues/364)).
+* Dependencies can now be defined pattern-free with `sequentialTestGroup` ([#343](https://github.com/UnkindPartition/tasty/issues/343)).
+* Added `--min-duration-to-report` flag that specifies the time a test must take before `tasty` outputs timing information ([#341](https://github.com/UnkindPartition/tasty/issues/341)).
+* When a test failed with an exception, print it using `displayException` instead of `show` ([#330](https://github.com/UnkindPartition/tasty/issues/330)).
 
 Version 1.4.3
 ---------------

core/Test/Tasty/Core.hs

@@ -159,7 +159,7 @@ resultSuccessful r =
 exceptionResult :: SomeException -> Result
 exceptionResult e = Result
   { resultOutcome = Failure $ TestThrewException e
-  , resultDescription = "Exception: " ++ show e
+  , resultDescription = "Exception: " ++ displayException e
   , resultShortDescription = "FAIL"
   , resultTime = 0
   , resultDetailsPrinter = noResultDetails

hunit/CHANGELOG.md

@@ -1,6 +1,11 @@
 Changes
 =======
 
+Unreleased
+---------------
+
+Provide an explicit implementation of `displayException` in `instance Exception HUnitFailure` ([#330](https://github.com/UnkindPartition/tasty/issues/330)).
+
 Version 0.10.0.3
 ----------------
 

hunit/Test/Tasty/HUnit/Orig.hs

@@ -135,7 +135,8 @@ instance (AssertionPredicable t) => AssertionPredicable (IO t)
 -- | Exception thrown by 'assertFailure' etc.
 data HUnitFailure = HUnitFailure (Maybe SrcLoc) String
     deriving (Eq, Show, Typeable)
-instance E.Exception HUnitFailure
+instance E.Exception HUnitFailure where
+  displayException (HUnitFailure mbloc s) = prependLocation mbloc s
 
 prependLocation :: Maybe SrcLoc -> String -> String
 prependLocation mbloc s =

hunit/Test/Tasty/HUnit/Steps.hs

@@ -25,10 +25,8 @@ instance IsTest TestCaseSteps where
         tme <- getTime
         atomicModifyIORef ref (\l -> ((tme,msg):l, ()))
 
-    hunitResult <- (Right <$> assertionFn stepFn) `catches`
-      [ Handler (\(HUnitFailure mbloc errMsg) -> return $ Left (prependLocation mbloc errMsg))
-      , Handler (\(SomeException ex)          -> return $ Left (show ex))
-      ]
+    hunitResult <- (Right <$> assertionFn stepFn) `catch`
+        \(SomeException ex) -> return $ Left (displayException ex)
 
     endTime <- getTime