[英]How can I use multi-line input with QuickCheck in doctest?
From Doctest's readme , one can use doctest with QuickCheck, like this: 从Doctest的自述文件中 ,可以使用带有QuickCheck的 doctest,如下所示:
-- |
-- prop> sort xs == (sort . sort) (xs :: [Int])
I would like to describe this property using multiple lines, probably like 我想用多行描述这个属性,可能就像
-- |
-- prop> sort xs ==
-- (sort . sort) (xs :: [Int])
Doctest itself supports multi-line input (again from readme) Doctest本身支持多行输入(同样来自自述文件)
-- |
-- >>> :{
-- let
-- x = 1
-- y = 2
-- in x + y + multiline
-- :}
-- 6
and I tried several similar syntaxes I came up with, such as 我尝试了几种类似的语法,比如
-- |
-- prop> :{ sort xs ==
-- (sort . sort) (xs :: [Int])
-- }:
without any success. 没有任何成功。 (In the example above, the error message is
parse error on input '{'
.) (在上面的示例中,错误消息是
parse error on input '{'
。)
How can I use multi-line input with Quickcheck in doctest? 如何在doctest中使用Quickcheck进行多行输入?
As of September 2017, doctest does not allow multi-line properties . 截至2017年9月, doctest不允许多行属性 。 However, you can use
quickCheck
as usual in a doctest: 但是,您可以像往常一样在doctest中使用
quickCheck
:
-- >>> import Test.QuickCheck
-- >>> import Data.List (sort)
-- >>> :{
-- quickCheck $ \xs ->
-- sort xs ==
-- (sort . sort) (xs :: [Int])
-- :}
-- +++ OK, passed 100 tests.
That's verbose, but will enable you to write arbitrary long checks. 这很冗长,但可以让你编写任意长检查。 Note that you can always create a
prop_*
function and use that in your doctest. 请注意,您始终可以创建
prop_*
函数并在doctest中使用它。
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