Question

使用mock编写单元测试时遇到问题。有一个我需要模拟的对象有很多getter，我在代码中调用它们。但是，这些不是我单元测试的目的。那么，是否有一种方法可以模拟所有方法而不是逐个模拟它们。

以下是代码示例：

public class ObjectNeedToMock{

private String field1;
...
private String field20;

private int theImportantInt;


public String getField1(){return this.field1;}
...

public String getField20(){return this.field20;}

public int getTheImportantInt(){return this.theImportantInt;}

}

这是我需要测试的服务类

public class Service{

public void methodNeedToTest(ObjectNeedToMock objectNeedToMock){
    String stringThatIdontCare1 = objectNeedToMock.getField1();
    ...
    String stringThatIdontCare20 = objectNeedToMock.getField20();
    // do something with the field1 to field20

    int veryImportantInt = objectNeedToMock.getTheImportantInt();
    // do something with the veryImportantInt

    }
}

在测试类中，测试方法就像

@Test
public void testMethodNeedToTest() throws Exception {
      ObjectNeedToMock o = mock(ObjectNeedToMock.class);
      when(o.getField1()).thenReturn(anyString());
      ....
      when(o.getField20()).thenReturn(anyString());

      when(o.getTheImportantInt()).thenReturn("1"); //This "1" is the only thing I care

}

那么，有没有办法可以避免将无用的“field1”的所有“when”写入“field20”

Answer 1

您可以控制模拟的默认答案。当您创建模拟时，请使用：

Mockito.mock(ObjectNeedToMock.class, new Answer() {
    @Override
    public Object answer(InvocationOnMock invocation) throws Throwable {
        /* 
           Put your default answer logic here.
           It should be based on type of arguments you consume and the type of arguments you return.
           i.e.
        */
        if (String.class.equals(invocation.getMethod().getReturnType())) {
            return "This is my default answer for all methods that returns string";
        } else {
            return RETURNS_DEFAULTS.answer(invocation);
        }
    }
}));

Answer 2

如果您对特定测试案例中getField1()到getField20()的结果不感兴趣，则根本不应该嘲笑它。换句话说，如果所有特定测试用例都应该关注getTheImportantInt()，那么您的测试用例应如下所示：

@Test
public void testMethodNeedToTest() throws Exception {
      ObjectNeedToMock o = mock(ObjectNeedToMock.class);
      when(o.getTheImportantInt()).thenReturn("1");

      // test code goes here
}

Answer 3

对于Kotlin用户：

val mocked:MyClassToMock = Mockito.mock(MyClassToMock::class.java,
                object:Answer<Any> {

            override fun answer(invocation: InvocationOnMock?): Any {
                    if (String::class.java.equals (invocation?.method?.getReturnType())) {
                        return "Default answer for all methods that returns string";
                    } else {
                        return Mockito.RETURNS_DEFAULTS.answer(invocation);
                    }
            }
        })

Mockito模拟所有方法调用并返回

3 个答案: