基于属性的测试在我预期失败时继续通过

Question

我相信这很简单。但是，以下测试将始终通过：

let transform number =  
    match number % 3, number % 5 with 
    | 0, 0 -> "FizzBuzz" 
    | _, 0 -> "Buzz" 
    | 0, _ -> "Fizz" 
    | _ -> number.ToString()

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

    Prop.forAll fiveAndThrees <| fun number ->

        let actual = transform number

        let expected = "jbdhjsdhjdsjhsdglsdjlljh"
        expected = actual

我也试过：

Check.QuickThrowOnFailure <| (expected = actual)

具体来说，为什么这个测试明明应该失败却仍然通过？

Answer 1

您正在创建属性，但从未真正检查过它。它只是坐在那里，从未执行过一次。

要检查属性，您需要将其传递给 Check.* 方法之一：

[<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

Answer 2

您还可以使用 FsCheck.Xunit 及其 [<Property>] 属性：

[<Property(QuietOnSuccess = true)>]
let ``FizzBuzz.transform returns FizzBuzz`` () =
    let fiveAndThrees =
        Arb.generate<int> |> Gen.map ((*) (3 * 5)) |> Arb.fromGen
    Prop.forAll fiveAndThrees <| fun number ->

        let actual = FizzBuzz.transform number

        let expected = "FizzBuzz"
        expected = actual

基于属性的测试在我预期失败时继续通过

Property-based test continues to pass when I expect it to fail

f#

property-based-testing

基于 属性 的测试在我预期失败时继续通过

Property-based test continues to pass when I expect it to fail

f#

property-based-testing

基于属性的测试在我预期失败时继续通过