java模拟自定义对象 [英] java mocking custom objects

问题描述

public class MainClass  {

    public void makeCall() {
        CustomObject obj = new CustomObject();
        obj.testMethod();
    }
}

我想对 makeCall() 进行单元测试.所以我必须模拟上面示例中的 CustomObject.我使用 Mockito 作为模拟框架.但是当我模拟像 mock(CustomObject.class) 这样的对象时.makeCall() 方法总是调用实际的对象而不是模拟的对象.反正有没有模拟本地对象.请帮忙

I want to unit test the makeCall(). So i have to mock the CustomObject in the above sample. I am using Mockito as the mock framework.But when i mock the object like mock(CustomObject.class). makeCall() method always call the actual object not the mocked one.Is there anyway to mock the local objects. Please help

推荐答案

MainClass 的单元测试友好版本应该注入 CustomObject，例如:

A unit-test-friendly version of your MainClass should have CustomObject injected, for example:

public class MainClass  {
    private CustomObject customObject = new CustomObject();  // a default one if none is provided

    public void setCustomObject(CustomObject customObject) {
        this.customObject = customObject;
    }

    public void makeCall() {
        this.customObject.testMethod();
    }
}

您的测试将如下所示:

CustomObject mockCustomObject = mock(CustomObject.class);
when(mockCustomObject.testMethod()).thenReturn(...);

MainClass sut = new MainClass();
sut.setCustomObject(mockCustomObject);

sut.makeCall();

verify(mockCustomObject).testMethod();

加上Mockito的注解，可以进一步简化为:

With Mockito's annotation, it can be further simplified as:

public class MyClassTest {
    @InjectMocks
    private MainClass mainClass;

    @Mock
    private CustomObject mockCustomObject;

    @Before
    public void setup() {
        MockitoAnnotations.initMocks(this);  // or use mockito runner
    }

    @Test
    public void testMakeCall() {
        when(mockCustomObject.testMethod()).thenReturn(...);
        mainClass.makeCall();
        verify(mockCustomObject).testMethod();
    }
}

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