如何使用起订量来模拟扩展方法？ [英] How do I use Moq to mock an extension method?

问题描述

我写一个测试，取决于扩展方法的结果，但我不希望扩展方法的未来未能打破过这个测试。嘲讽这个结果似乎是显而易见的选择，但起订量似乎并没有提供一种方式来覆盖静态方法（一个用于扩展方法要求）。没有与Moq.Protected和Moq.Stub有类似的想法，但他们似乎并没有提供这种情况下任何东西。我缺少的东西或我应该要对此以不同的方式？

I am writing a test that depends on the results of an extension method but I don't want a future failure of that extension method to ever break this test. Mocking that result seemed the obvious choice but Moq doesn't seem to offer a way to override a static method (a requirement for an extension method). There is a similar idea with Moq.Protected and Moq.Stub, but they don't seem to offer anything for this scenario. Am I missing something or should I be going about this a different way?

下面是失败与通常的的无效的非可覆盖件上的期望一个简单的例子的。这是需要嘲笑扩展方法的一个坏榜样，但它应该做的。

Here is a trivial example that fails with the usual "Invalid expectation on a non-overridable member". This is a bad example of needing to mock an extension method, but it should do.

public class SomeType {
    int Id { get; set; }
}

var ListMock = new Mock<List<SomeType>>();
ListMock.Expect(l => l.FirstOrDefault(st => st.Id == 5))
        .Returns(new SomeType { Id = 5 });

对于任何TypeMock迷们可能会建议我用隔离来代替：我AP preciate因为它看起来像TypeMock可以做的工作蒙住眼睛，醉醺醺的，但我们的预算不会很快增加任何时间的努力

As for any TypeMock junkies that might suggest I use Isolator instead: I appreciate the effort since it looks like TypeMock could do the job blindfolded and inebriated, but our budget isn't increasing any time soon.

推荐答案

扩展方法是变相的只是静态方法。像起订量或RhinoMocks的嘲讽框架只能创建对象的实例模拟，这意味着嘲讽静态方法是不可能的。

Extension methods are just static methods in disguise. Mocking frameworks like Moq or Rhinomocks can only create mock instances of objects, this means mocking static methods is not possible.

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