使用 Mockito 模拟类的成员变量

Mocking member variables of a class using Mockito(使用 Mockito 模拟类的成员变量)

问题描述

我是开发新手，尤其是单元测试新手.我想我的要求很简单，但我很想知道其他人对此的想法.

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.

假设我有两个这样的课程 -

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来测试 First.doSecond() 方法.但是，假设我想像这样模拟 Second.doSecond() 类.我正在使用 Mockito 来做到这一点.

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并且断言失败.有没有办法模拟我要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

你需要提供一种访问成员变量的方法，这样你就可以传入一个 mock(最常见的方法是 setter 方法或构造函数一个参数).

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).

如果您的代码未提供执行此操作的方法，则它被错误地考虑为 TDD(测试驱动开发).

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

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