如何对作为 Mockito 中的构建器类的方法参数进行单元测试？

Question

I have a dependency in the Spring Boot which is called from my class. This dependency makes a call with a newly instantiated builder pattern class as an argument. I need to know if it is possible to verify if this single builder class was constructed with certain values when the dependency call is made, eg:

public class MyClass {

  @Autowired
  private MyDep myDep;

  public void callMyDepService() {
    myDep.serviceCall(new MyBuilder().paramOne("One").paramTwo("Two").build());
  }

}

As you can see, a new MyBuilder is instantiated every time, so I can't just use Mockito's eq() to match the arguments' value.

Answer 1

I would like to make sure callMyDepService calls myDep.serviceCall with certain parameter values.

Using a captor seems to be the easiest way to do that. Something like this, where SomeClass is the class your MyBuilder builds.

@ExtendWith(MockitoExtension.class)
public class CaptureTest {

    @InjectMocks
    MyClass classUnderTest;

    @Mock
    MyDep myDep;

    @Test
    public void test() {

        classUnderTest.callMyDepService();

        Captor<SomeClass> captor = ArgumentCaptor.forClass(SomeClass.class);
        Mockito.verify(myDep).serviceCall(captor.capture());

        SomeClass parameter = captor.getValue();
        // do assertions
    }
}