Question

所以我有一个属性p :: Int -> Bool。我需要使用自定义生成器g :: Gen Int对其进行测试。这行得通，我可以跑步

quickCheckResult $ forAll g p

但是我希望它运行100多个测试。该文档说使用withMaxSuccess。这适用于

quickCheck (withMaxSuccess 1000 p)

但不是

quickCheckResult $ forAll g (withMaxSuccess 1000 p)

因为它会导致：

<interactive>:38:23: error:
    • Couldn't match expected type ‘Int -> prop0’
                  with actual type ‘Property’
    • Possible cause: ‘withMaxSuccess’ is applied to too many arguments
      In the second argument of ‘forAll’, namely
        ‘(withMaxSuccess 10000 p)’
      In the expression:
        forAll g (withMaxSuccess 10000 p)
      In an equation for ‘it’:
          it = forAll g (withMaxSuccess 10000 p)

似乎withMaxSuccess将Int->Bool设为Property

如何以任意数量运行forAll？

Answer 1

您只需要稍稍不同地组成表达式即可

quickCheckResult $ withMaxSuccess 1000 $ forAll g p

或者，如果您喜欢方括号：

quickCheckResult ((withMaxSuccess 1000) (forAll g p))

查看类型应解释其工作原理：

Prelude Test.QuickCheck> :t forAll g p
forAll g p :: Property

Prelude Test.QuickCheck> :t withMaxSuccess 1000
withMaxSuccess 1000 :: Testable prop => prop -> Property

Prelude Test.QuickCheck> :t (withMaxSuccess 1000) (forAll g p)
(withMaxSuccess 1000) (forAll g p) :: Property

由于Property是Testable实例，因此类型会排列。

如何更改自定义生成器的测试量？

1 个答案: