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1. module Test.QuickCheck

   The QuickCheck manual gives detailed information about using QuickCheck effectively. You can also try https://begriffs.com/posts/2017-01-14-design-use-quickcheck.html, a tutorial written by a user of QuickCheck. To start using QuickCheck, write down your property as a function returning Bool. For example, to check that reversing a list twice gives back the same list you can write:

   import Test.QuickCheck
   
   prop_reverse :: [Int] -> Bool
   prop_reverse xs = reverse (reverse xs) == xs
   

   You can then use QuickCheck to test prop_reverse on 100 random lists:

   >>> quickCheck prop_reverse
   +++ OK, passed 100 tests.
   

   To run more tests you can use the withMaxSuccess combinator:

   >>> quickCheck (withMaxSuccess 10000 prop_reverse)
   +++ OK, passed 10000 tests.
   

   To use QuickCheck on your own data types you will need to write Arbitrary instances for those types. See the QuickCheck manual for details about how to do that. When testing fails quickCheck will try to give you a minimal counterexample to your property: @ import Test.QuickCheck prop_reverse_bad :: [Int] -> Bool prop_reverse_bad xs = reverse xs == xs

   >>> quickCheck prop_reverse_bad
   *** Failed! Falsified (after 3 tests and 3 shrinks):
   [0,1]
   @
   

   However, beware because not all properties that ought to fail will fail when you expect them to:

   >>> quickCheck $  x y -> x == y
   +++ Ok, passed 100 tests.
   

   That's because GHCi will default any type variables in your property to (), so in the example above quickCheck was really testing that () is equal to itself. To avoid this behaviour it is best practise to monomorphise your polymorphic properties when testing:

   >>> quickCheck $  x y -> (x :: Int) == y
   *** Failed! Falsified (after 4 tests and 3 shrinks):
   0
   1
   

2. module Test.Hspec.QuickCheck

   No documentation available.

3. module Test.Tasty.QuickCheck

   This module allows to use QuickCheck properties in tasty.

4. module Test.Hspec.Core.QuickCheck

   No documentation available.

5. module Test.Hspec.Wai.QuickCheck

   No documentation available.

6. QuickCheck :: Property -> Property

   quickcheck-simple	Test.QuickCheck.Simple

   No documentation available.

7. module Test.Sandwich.QuickCheck

   Functions for introducing QuickCheck tests into a Sandwich test tree. Modelled after Hspec's version. Documentation can be found here.

8. quickCheck :: Testable prop => prop -> IO ()

   QuickCheck	Test.QuickCheck

   Tests a property and prints the results to stdout. By default up to 100 tests are performed, which may not be enough to find all bugs. To run more tests, use withMaxSuccess. If you want to get the counterexample as a Haskell value, rather than just printing it, try the quickcheck-with-counterexamples package.

9. quickCheck :: Testable prop => prop -> IO ()

   massiv-test	Test.Massiv.Utils

   Tests a property and prints the results to stdout. By default up to 100 tests are performed, which may not be enough to find all bugs. To run more tests, use withMaxSuccess. If you want to get the counterexample as a Haskell value, rather than just printing it, try the quickcheck-with-counterexamples package.

10. newtype QuickCheckMaxRatio

    tasty-quickcheck	Test.Tasty.QuickCheck

    Maximum number of of discarded tests per successful test before giving up.

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