[JAVA] How to mock a super method call in PowerMock

Introduction

In JUnit using Mockito and Powermock, I had to mock the processing of the parent class using super, so I made a note of it. If you look it up, you can use PowerMockito.suppress () quite a bit, but if you use suppress (), it will only be skipped, and you should return the mock object you expected. I was in a state where I couldn't execute the subsequent processing of JUnit successfully.

Tested class

The sample code is shown below. The DTO class is omitted.

Parent class

public class Parent {

	public OutputDto execute (InputDto input) {
		System.out.println("Parent#execute()");
		OutputDto out = new OutputDto();
		out.setText(input.getText());
		return out;
	}
}

Child class

public class Child extends Parent {

	public OutputDto execute (InputDto input) {
		System.out.println("Child#execute()");
		OutputDto out = super.execute(input);
		out.setText(out.getText()+" updated in Child.");
		return out;
	}
}

The point is that in the child class, super.execute () is done and the return value is expected.

JUnit test class

@RunWith(PowerMockRunner.class)
@PrepareForTest({Parent.class})//Specify parent
public class MockSuperTest {

	//Tested class
	@InjectMocks
	private Child child;

	@Before
	public void setUp() throws Exception {
		MockitoAnnotations.initMocks(this);
	}

	@Test
	public void testExecute1() {
		//Input data preparation
		InputDto input = new InputDto();
		input.setText("hello");
		OutputDto result = new OutputDto();
		result.setText("hello updated in Child.");

		try {
			Method method = child.getClass().getMethod("execute", InputDto.class);
			PowerMockito.replace(method).with(
				new InvocationHandler() {
					@Override
					public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
						System.out.println("replaced execute()!!");
						return result;
					}
				});
		} catch (Exception e) {
			e.printStackTrace();
			fail();
		}

		OutputDto testOut = child.execute(input);
		assertEquals(result.getText(), testOut.getText());
	}
}

Execution result

When you run JUnit above,

Child#execute()
replaced execute()!!

Then, after calling ʻexecute ()of the child class,super.execute ()is replaced with the content specified byPowerMockito.replace ()`.

By the way,

@PrepareForTest({Child.class})//Specify a child
public class MockSuperTest {

If you specify the place in the child class, the result will be

replaced execute()!!

Directly change ʻexecute ()` of the neighboring child class. Of course if you run it normally

Child#execute()
Parent#execute()

Is the expected value.

that's all.