How to make Test-Framework to report about the reason of QuickCheck's fail?

Question

For example I have a testing code like this:

import Data.Decimal
import Data.Ratio
import Data.Word
import Test.HUnit
import Control.Applicative

import Debug.Trace

import Test.QuickCheck
import qualified Test.QuickCheck.Property as P
import Test.Framework as TF (defaultMain, testGroup, Test)
import Test.Framework.Providers.HUnit
import Test.Framework.Providers.QuickCheck2 (testProperty)

...........

isEQ :: (Eq a, Show a) => a -> a -> P.Result
isEQ a b = if a == b
           then P.succeeded
           else P.failed {P.reason = show a ++ "\nis not equal to \n" ++ show b}

-- | "read" is the inverse of "show".
-- 
-- > read (show n) == n
prop_readShow :: Decimal -> P.Result
prop_readShow d =  isEQ (read (show d)) d

.............

tests = [
        testGroup "QuickCheck Data.Decimal" [
                testProperty "readShow"           prop_readShow,
                testProperty "readShowPrecision"  prop_readShowPrecision,
                testProperty "fromIntegerZero"    prop_fromIntegerZero, 

.................

the report of test-framerowk looks like this

 dist/build/Main/Main -a2000   
QuickCheck Data.Decimal:
  readShow: [Failed]
Arguments exhausted after 0 tests
  readShowPrecision: [Failed]
Arguments exhausted after 0 tests
  fromIntegerZero: [Failed]

without any reason of the fail. The same looking HSpec tests print the fail reason in the report, but test-framework tests does not.

Answer 1

The likely problem here is that QuickCheck is giving up after finding too many unsuitable test cases. Raising topt_maximum_unsuitable_generated_tests will give QuickCheck more opportunities to find acceptable cases and allow the test to finish.

Answer 2

That was a different issue, in fact test-framework-0.8 has a bug https://github.com/batterseapower/test-framework/issues/34 so the high values of tests count (-a parameter) lead to fail.

You just need to reduce the version of test-framework to 0.7.