使用Mockito模拟类的成员变量 [英] Mocking member variables of a class using Mockito

问题描述

我是开发新手，特别是单元测试。
我想我的要求很简单，但我很想知道其他人的想法。

I am a newbie to development and to unit tests in particular . I guess my requirement is pretty simple, but I am keen to know others thoughts on this.

假设我有两个类似的东西 -

Suppose I have two classes like so -

public class First {

    Second second ;

    public First(){
        second = new Second();
    }

    public String doSecond(){
        return second.doSecond();
    }
}

class Second {

    public String doSecond(){
        return "Do Something";
    }
}

假设我正在编写单元测试以测试 First.doSecond（）方法。但是，假设我想模拟 Second.doSecond（）这样的类。我正在使用Mockito这样做。

Let's say I am writing unit test to test First.doSecond() method. However, suppose, i want to Mock Second.doSecond() class like so. I am using Mockito to do this.

public void testFirst(){
    Second sec = mock(Second.class);
    when(sec.doSecond()).thenReturn("Stubbed Second");

    First first = new First();
    assertEquals("Stubbed Second", first.doSecond());
}

我看到模拟没有生效，断言失败。
有没有办法模拟我想测试的类的成员变量。 ？

I am seeing that the mocking does not take effect and the assertion fails. Is there no way to mock the member variables of a class that I want to test . ?

推荐答案

您需要提供一种访问成员变量的方法，以便您可以传入模拟（最常见的方式是一个setter方法或一个带参数的构造函数）。

You need to provide a way of accessing the member variables so you can pass in a mock (the most common ways would be a setter method or a constructor which takes a parameter).

如果你的代码没有提供这样做的方法，那么TDD（测试驱动开发）就会错误地考虑它。

If your code doesn't provide a way of doing this, it's incorrectly factored for TDD (Test Driven Development).

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