java 用 Mockito 模拟“内部”对象

Mock "inner" object with Mockito

提问by RRZ Europe

Quite new to unittesting and mockito, I have a method to test which calls a method on a new object. how can I mock the inner object?

对单元测试和模拟非常新，我有一个方法来测试它在新对象上调用方法。我如何模拟内部对象？

methodToTest(input){
...
OtherObject oo = new OtherObject();
...
myresult = dosomething_with_input;
...
return myresult + oo.methodX();
}

can I mock oo to return "abc"? I really do only want to test my code, but when I mock "methodToTest" to return "42abc", then I will not test my "dosomething_with_input"-code ...

我可以模拟 oo 返回“abc”吗？我真的只想测试我的代码，但是当我模拟“methodToTest”返回“42abc”时，我不会测试我的“dosomething_with_input”代码......

回答by rcomblen

I consider the class that implements methodToTestis named ClassToTest

我认为实现的类methodToTest被命名ClassToTest

• Create a factory class for OtherObject
• Have the factory as a field of ClassToTest
• either
  • pass the factory as parameter of the constructor of ClassToTest
  • or initialize it when allocating the ClassToTestobject and create a setter for the factory

• 创建一个工厂类 OtherObject
• 有工厂作为一个领域 ClassToTest
• 任何一个
  • 将工厂作为构造函数的参数传递 ClassToTest
  • 或者在分配ClassToTest对象时初始化它并为工厂创建一个setter

your test class should look like

你的测试类应该看起来像

public class ClassToTestTest{
    @Test
    public void test(){
        // Given
        OtherObject mockOtherObject = mock(OtherObject.class);
        when(mockOtherObject.methodX()).thenReturn("methodXResult");
        OtherObjectFactory otherObjectFactory = mock(OtherObjectFactory.class);
        when(otherObjectFactory.newInstance()).thenReturn(mockOtherObject);
        ClassToTest classToTest = new ClassToTest(factory);

        // When
        classToTest.methodToTest(input);

        // Then
        // ...
    }
}