如何为FsUnit提供有用的断言失败消息?

时间:2017-04-13 13:32:06

标签: f# nunit fsunit

我正在使用FsUnit 2.3.2,我对失败消息不满意。请参阅以下示例:

[<Test>]
let ``test 1``() =
    [1; 3]
    |> should equal [1;2]

...给了我不那么有用的信息:

  

预期和实际都是   Microsoft.FSharp.Collections.FSharpList`1 [System.Int32]

     

at FsUnit.TopLevelOperators.should [a,a](FSharpFunc`2 f,a x,Object y)   在d:\ GitHub \ FsUnit \ src \ FsUnit.NUnit \ FsUnit.fs:Program.test第44行   1:()在F:\ work \ playground \ fsunit \ fsunit \ Program.fs:第9行

我找到的解决方法是使用数组而不是列表:

[<Test>]
let ``test 2``() =
    [|1; 4|]
    |> should equal [|1;2|]

...产生

  

预期和实际都是System.Int32 [2]
    值[1]的值不同     预期:2
    但是:4

第二个问题是我是否定义了ADT

type MyT = 
    A of int 
    | B of string

[<Test>]
let ``test 4``() =
    A 10
    |> should equal (B "abc")

...给我留言:

  

预期:计划+ MyT + B
    但是:Program + MyT + A

...我可以通过为MyT实现ToString来解决这个问题:

override this.ToString() = match this with
    | A i -> sprintf "A(%d)" i
    | B s -> sprintf "B(%s)" s

...这会产生一个好消息:

  

预期:B(abc)
    但是:A(10)

...但是我希望fsunit能够以某种方式呈现MyT值(sprintf“%A”)。

无论如何,不​​得不做这些变通办法。

如何在不使用数组的情况下获取F#列表的有用消息?

如何获取ADT的有用信息?

对于上述问题是否有一个很好的解决方法,或者我应该放弃FsUnit?

对于没有这些问题的F#单元测试库,你有更好的建议吗?

1 个答案:

答案 0 :(得分:2)

有几个竞争者:

<强> Expecto

[<Tests>]
let tests =
  testList "test group" [
    testCase "strings" <| fun _ ->
        let subject = "Hello World"
        Expect.equal subject "Hello world"
                    "The strings should be equal"

    testCase "lists" <| fun _ ->
        let expected = [1; 2]   
        Expect.equal expected [1; 3]
                    "The lists should be equal"

    testCase "DUs" <| fun _ ->
        let expected = A 10   
        Expect.equal expected (B "abc")
    ]

输出

[19:29:46 INF] EXPECTO? Running tests...
[19:29:46 ERR] test group/strings failed in 00:00:00. 
The strings should be equal.
          Expected string to equal:
          "Hello world"
                 ↑
          The string differs at index 6.
          "Hello World"
                 ↑
          String does not match at position 6. Expected char: 'w', but got 'W'.

[19:29:46 ERR] test group/lists failed in 00:00:00. 
The lists should be equal. Actual value was [1; 2] but had expected it to be [1; 3].

[19:29:46 ERR] test group/DUs failed in 00:00:00. 
The DUs should be equal. Actual value was A 10 but had expected it to be B "abc".

[19:29:46 INF] EXPECTO! 3 tests run in 00:00:00.0028417 – 0 passed, 0 ignored, 3 failed, 0 errored. ( ರ Ĺ̯ ರೃ )
val it : int = 1

<强> Unquote

[<Test>]
let ``The strings should be equal`` () =
    let subject = "Hello World"
    subject =! "Hello world"
Result Message:   
"Hello World" = "Hello world"
false
[<Test>]
let ``The lists should be equal`` () =
    let expected = [1; 2]
    expected =! [1; 3]
Result Message:   
[1; 2] = [1; 3]
false
[<Test>]
let ``The DUs should be equal`` () =
    let expected = A 10
    expected =! (B "abc")
Result Message:   
A 10 = B "abc"
false

Unquote的好处在于它的Quotations,允许逐步失败的消息。

[<Test>]
let ``The arrays should be equal`` () =
    let expected = [|0 ; 2 ; 3 ; 4|]
    test <@ (Array.map ((+) 1) [|0 .. 3|]) = expected @>
Result Message:   
Array.map ((+) 1) [|0..3|] = [|0; 2; 3; 4|]
Array.map ((+) 1) [|0; 1; 2; 3|] = [|0; 2; 3; 4|]
[|1; 2; 3; 4|] = [|0; 2; 3; 4|]
false