如何解释基于属性的测试代码？

Question

如何解释基于属性的测试代码？

我正在努力翻译以下 sn-p 的说明：

let myProperty = Prop.forAll fiveAndThrees <| fun number ->

    let actual = transform number

    let expected = "jbdhjsdhjdsjhsdglsdjlljh"
    expected = actual

Check.QuickThrowOnFailure myProperty

具体来说，我正在与向后管道运算符（即“

这是测试：

[<Fact>]
let ``FizzBuzz.transform returns FizzBuzz`` () =
    let fiveAndThrees = Arb.generate<int> |> Gen.map ((*) (3 * 5)) 
                                          |> Arb.fromGen

    let myProperty = Prop.forAll fiveAndThrees <| fun number ->

        let actual = transform number

        let expected = "jbdhjsdhjdsjhsdglsdjlljh"
        expected = actual

    Check.QuickThrowOnFailure myProperty

有人可以指导我逐步了解此代码的工作原理吗？

可以使用正向管道运算符（即“|>”）重写吗？

Answer 1

此答案仅涵盖为什么使用<| 而不是|>。

这里有 5 个示例，它们致力于将 <| 用于大型函数。第 6 个示例是使用 |> 而不是 <| 显示代码的外观。关键是使用|> 的第6 个示例，您必须查看代码以找到主要功能funThatNeedsListAndFunc，但对于<|，主要功能funThatNeedsListAndFunc 是显而易见的。因此，当最后一个参数是函数时，您通常会看到 <|，并且您希望在主函数之后传入该函数以便于理解。就这样;不要阅读更多内容。

在阅读了 Mark 的博客后，我还了解到 <| 对于删除 ( ) 周围的 fun 很有用。使用( )的例子如例7所示。

let funThatNeedsListAndFunc list func =
    func list

let func = List.sum
let list = Seq.toList { 0 .. 5}

let result1 = funThatNeedsListAndFunc list func

printfn "result1: %A" result1

let result2 = funThatNeedsListAndFunc list <| func

printfn "result2: %A" result2

let result3 = funThatNeedsListAndFunc list <| List.sum

printfn "result3: %A" result3

let result4 = funThatNeedsListAndFunc list <| 
    fun (list : 'a list) -> List.sum list

printfn "result4: %A" result4

let result5 = funThatNeedsListAndFunc list <| 
    fun (list : 'a list) -> 
        // This will be a long function
        let a = 1
        let b = 2
        let c = a * b
        let result = List.sum list
        let d = "more useless lines"
        let (e,f,g) = ("a", 15, 3.0)
        result

printfn "result5: %A" result5

.

let result6 = 
    fun (list : 'a list) -> 
        // This will be a long function
        let a = 1
        let b = 2
        let c = a * b
        let result = List.sum list
        let d = "more useless lines"
        let (e,f,g) = ("a", 15, 3.0)
        result
    |> funThatNeedsListAndFunc list

printfn "result6: %A" result6

.

let result7 = 
    funThatNeedsListAndFunc list (fun (list : 'a list) -> 
        // This will be a long function
        let a = 1
        let b = 2
        let c = a * b
        let result = List.sum list
        let d = "more useless lines"
        let (e,f,g) = ("a", 15, 3.0)
        result)

printfn "result7: %A" result7