我试图从_prop示例转到在Tasty中写相同的东西。 (例如http://primitive-automaton.logdown.com/posts/142511/tdd-with-quickcheck)
game9_prop :: Game9 -> Bool
game9_prop = (9==) . length . unGame . unGame9
这就是我尝试的美味:
qcTestGengame9 :: TestTree
qcTestGengame9 = QC.testProperty "Better gen rate" $
\ (g :: Game9) -> length . unGame . unGame9 g == 9 --ERROR LINE
此转换为我提供了以下错误:
test/Tasty.hs:53:11:
Illegal type signature: `Game9'
Perhaps you intended to use -XScopedTypeVariables
In a pattern type-signature
这是Game9类型:
-- To make generation rate better
newtype Game9 = Game9 { unGame9 :: Game }
deriving (Eq, Show)
instance Arbitrary Game9 where
arbitrary = (Game9 . Game) `liftM` replicateM 9 arbitrary
答案 0 :(得分:3)
要修复即时错误,请删除类型注释,即使用
qcTestGengame9 :: TestTree
qcTestGengame9 = QC.testProperty "Better gen rate" $
\ g -> (length . unGame . unGame9) g == 9
表达式unGame9 g
已确保g :: Game9
。
但实际上它更简单:定义game9_prop
后,您可以使用
qcTestGengame9 :: TestTree
qcTestGengame9 = QC.testProperty "Better gen rate" game9_prop