問題描述

在我的模擬類中，我正在模擬方法 foo().對于某些測試用例，我希望 foo() 的模擬實現(xiàn)返回一個特殊值.對于其他測試用例，我想使用 foo() 的真正實現(xiàn).我在我的模擬類中定義了一個布爾值，以便我可以在模擬方法中確定是要返回特殊值還是使用真實"方法.問題是，我似乎無法弄清楚如何從模擬方法中調用真實方法.

In my mock class, I'm mocking method foo(). For some test cases, I want the mock implementation of foo() to return a special value. For other test cases, I want to use the real implementation of foo(). I have a boolean defined in my mock class so that I can determine in the mock method whether I want to return the special value, or use the "real" method. The problem is, I can't seem to figure out how to call the real method from the mocked method.

我發(fā)現(xiàn)您可以在名為it"的模擬對象中定義一個特殊成員(具有被模擬對象的類型).這允許您從模擬實現(xiàn)中引用真實的類.所以，我的計劃是，如果我需要調用 foo() 的真實"實現(xiàn)，模擬方法將調用 it.foo().但是，這不起作用，因為調用 it.foo() 只是再次調用模擬版本，而不是真實版本，所以我最終得到了無限遞歸.

I found that you can define a special member within the mock object named "it" (with type of the object being mocked). This allows you to reference the real class from the mock implementation. So, my plan was, if I needed to invoke the "real" implementation of foo(), the mock method would call it.foo(). However, this doesn't work, because calling it.foo() just calls the mock version again, not the real version, so I end up with infinite recursion.

有什么辦法可以讓這個工作嗎?

Is there some way to make this work?

使用代碼示例可能會更清楚，這是我當前的模擬方法實現(xiàn)的樣子:

it might be clearer with a code example, here's what my current mocked method implementation looks like:

private RealClass it;
...
public SomeClass foo() {
    if(fakeIt) {
        return new SomeClass("fakevalue");
    } else {
        // doesn't work, just keeps calling the mock foo
        // in infinite recursion
        return it.foo();
    }
}

編輯 2:另外，對于我的大多數(shù)測試用例，我確實不想要模擬實現(xiàn).所以我最初的嘗試是只在我需要模擬對象的那些測試用例中調用 Mockit.redefineMethods() .但這不起作用 - 似乎您只能在 setup/teardown 中執(zhí)行此操作......當我嘗試這樣做時，我的模擬實現(xiàn)從未被調用.

EDIT 2: Also, for most of my test cases I do NOT want the mock implementation. So my initial attempt at this was to only call Mockit.redefineMethods() within those test cases where I needed the mock object. But this didn't work - it seems you can only do this within setup/teardown ... my mock implementation never got called when I tried that.

解決方案說明:

起初我不認為給出的答案有效，但在玩了一些之后，問題似乎是我將 JMockit 核心"方法與注釋"驅動方法混合在一起.顯然，在使用注釋時，您需要使用 Mockit.setupMocks，而不是 Mockit.redefineMethods().這就是最終奏效的方法:

At first I didn't think the answer given worked, but after playing with it some more, it seems the problem is that I was mixing JMockit "core" methods with the "annotation" driven methods. Apparently when using the annotation you need to use Mockit.setupMocks, not Mockit.redefineMethods(). This is what finally worked:

@Before 
public void setUp() throws Exception
{
    Mockit.setUpMocks(MyMockClass.class);
}

然后，對于模擬類:

@MockClass(realClass = RealClass.class)
public static class MyMockClass {
    private static boolean fakeIt = false;
    private RealClass it;

    @Mock(reentrant = true)
    public SomeClass foo() {
        if(fakeIt) {
            return new SomeClass("fakevalue");
        } else {
            return it.foo();
        }
    }
}

推薦答案

我認為你可以使用 @Mock 注釋來做到這一點.從文檔中，您的模擬類上的 @Mock(reentrant=true) 應該這樣做.

I think you can do this with the @Mock annotation. From the docs, @Mock(reentrant=true) on your mock class should do it.

請參閱 http://jmockit.googlecode.com/svn/trunk/www/javadoc/mockit/Mock.html
例如看這里 http://jmockit.googlecode.com/svn/trunk/www/tutorial/StateBasedTesting.html#reentrant

不過我還沒有測試過..

I haven't tested this though..

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