Mockito 的动态返回值 [英] Dynamic return values with Mockito

问题描述

通常为 Mockito 模拟定义返回值，如下所示:

One typically defines return values for a Mockito mock as follows:

MyClass myClass = Mockito.mock(MyClass.class);
when(myClass.myMethod()).thenReturn(0, 100, 200, ...);

有没有办法通过提供种子和函数来动态地做到这一点，例如:

Is there a way to this dynamically by supplying a seed and a function, e.g.:

when(mock.myMethod()).thenReturn(seed, previousVal -> previousVal + 100);

推荐答案

是的，您可以返回一个org.mockito.stubbing.Answer.

Yes, you can return an org.mockito.stubbing.Answer.

class AddingAnswer implements Answer {
    int current = 0;
    public Object answer(InvocationOnMock invocation) {
        int result = current;
        current += 100;
        return result;
    }
}

然后你可以像这样连接到你的模拟

which you can then wire to your mock like this

Answer answer = new AddingAnswer();
when(myClass.myMethod()).then(answer);

或者在你想要的通用版本中

Or in the generic version you want

class DynamicAnswer<T> implements Answer {
    T currentValue;
    UnaryOperator<T> adjustment;
    public DynamicAnswer(T seed, UnaryOperator<T> ad) {
        currentValue = seed;
        adjustment = ad;
    }
    public Object answer(InvocationOnMock invocation) {
        T result = currentValue;
        currentValue = adjustment.apply(currentValue);
        return result;
    }
}

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