我该如何在OCMockito中添加类方法? [英] How do I stub a class method with OCMockito?

问题描述

OCMockito文档声称可以模拟类对象，但是我无法确定如何解决.以下测试失败，并显示Expected "Purple" but was "":

The OCMockito documentation claims it's possible to mock class objects, but I'm damned if I can work out how. The following test fails with Expected "Purple" but was "":

- (void)testClassMethodMocking
{
    Class stringClassMock = mockClass([NSString class]);
    [given([stringClassMock string]) willReturn:@"Purple"];

    assertThat([NSString string], equalTo(@"Purple"));
}

如果以上链接的常见问题解答如何模拟类对象?"的答案 not 暗示是否有可能将类方法的返回值存根，它用于什么 ?

If the answer to the abovelinked FAQ section "How do you mock a class object?" does not imply it's possible stub the return value of a class method, what is it used for?

当然，以上只是一个退化的示例，实际的[NSString string]调用位于被测方法内部:

Of course the above is a degenerate example, the real [NSString string] call is inside the method under test:

- (NSString *)methodThatCallsAClassMethod
{
    return [NSString string];
}

...使上面的断言看起来像:

... making the assert above look like:

assertThat([testedObject methodThatCallsAClassMethod], equalTo(@"Purple"));

因此，上述完全无效的方法行不通吗?那么，我如何实现我想在这里做的事情?

So the above just flat-out won't work? How do I achieve what I want to do here, then?

推荐答案

您的断言语句直接使用NSString.改用模拟:

Your assertion statement is using NSString directly. Use the mock instead:

assertThat([stringClassMock string], equalTo(@"Purple"));

换句话说，该模拟不会使实际的NSString混乱.而是它的替身.

In other words, the mock isn't swizzling the actual NSString. Rather, it's a stand-in for it.

在您编辑的示例中，您的"methodThatCallsAClassMethod"对NSString具有依赖性.如果要替换它，则需要注入类或Subclass and Override Method.

In your edited example, your "methodThatCallsAClassMethod" has a dependency on NSString. If you wanted to replace that, you either need to inject the class, or Subclass and Override Method.

注射:

return [self.stringClass string];

然后，您可以将stringClass属性设置为模拟对象.

Then you can set the stringClass property to a mock.

子类和覆盖方法:

@interface TestingFoo : Foo
@end

@implementation @TestingFoo

- (NSString *)methodThatCallsAClassMethod
{
    // return whatever you want
}

@end

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