比较歧视联盟 [英] Comparing Discriminated Unions

问题描述

我是F#的新手，并且正在使用FParsec.我将使用FParsec生成AST.我想使用FsUnit围绕解析器的各个部分编写一些测试，以确保正确的操作.

I'm a newbie to F# and I'm playing around with FParsec. I would use FParsec to generate an AST. I would like to use FsUnit to write some tests around the various parts of the parser to ensure correct operation.

我在语法上有点麻烦(对不起，确切的代码在起作用，我可以稍后再发布一个特定的示例)，那么一个人如何比较两个有区别的并集(一个是期望的，另一个是实际的)结果)?有人可以使用FsUnit(或NUnit)提供一个很小的代码示例吗?

I'm having a bit of trouble with the syntax (sorry, the exact code is at work, I can post a specific example later) so how exactly could one compare two discriminated unions (one the expected, the other the actual result)? Could someone provide a tiny code example using FsUnit (or NUnit), please?

歧视工会的例子(非常简单)

An example discriminated union (very simple)

type AST = 
    | Variable of string
    | Class of string
    | Number of int

推荐答案

正如Brian所指出的那样，F#联合具有结构相等性，因此无论您喜欢使用哪种单元测试框架，都可以轻松实现.

Since, as Brian pointed out, F# unions have structural equality, this is easy using whichever unit testing framework you are fond of.

FsUnit是在NUnit之上构建的特定于F#的库.我个人最喜欢的F#特定单元测试库是取消引用 ;;)，该框架与框架无关，与NUnit，xUnit.net，MbUnit甚至在FSI内都可以很好地工作.您可能会对此与以下内容的比较感兴趣FsUnit.

FsUnit is an F# specific library built on top of NUnit. My personal favorite F# specific unit testing library is Unquote, ;), which is framework agnostic, working very well with NUnit, xUnit.net, MbUnit, ... or even within FSI. You may be interested in this comparison with FsUnit.

那么，您将如何使用NUnit + Unquote来做到这一点?这是一个完整的工作示例:

So, how would you do this with NUnit + Unquote? Here's a full working example:

module UnitTests

open NUnit.Framework
open Swensen.Unquote

type AST = 
    | Variable of string
    | Class of string
    | Number of int

let mockFParsec_parseVariable input = Variable(input)

[<Test>]
let ``test variable parse, passing example`` () =
    test <@ mockFParsec_parseVariable "x" = Variable("x") @>

[<Test>]
let ``test variable parse, failing example`` () =
    test <@ mockFParsec_parseVariable "y" = Variable("x") @>

然后使用TestDriven.NET运行测试，输出如下:

Then running the tests using TestDriven.NET, the output is as follows:

------ Test started: Assembly: xxx.exe ------

Test 'UnitTests.test variable parse, failing example' failed: 

UnitTests.mockFParsec_parseVariable "y" = Variable("x")
Variable "y" = Variable("x")
false
    C:\xxx\UnitTests.fs(19,0): at UnitTests.test variable parse, failing example()

1 passed, 1 failed, 0 skipped, took 0.80 seconds (NUnit 2.5.10).

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