How to use shouldInjectWithInvalidReference method of org.mockitousage.junitrule.InvalidTargetMockitoJUnitRuleTest class

Spring's MockHttpServletRequest and MockHttpServletResponse are useful for that purpose. E.g.

    MockHttpServletRequest request = new MockHttpServletRequest();
    MockHttpServletResponse response = new MockHttpServletResponse();
    request.addHeader(HttpHeaders.HOST, "myhost.com");
    request.setLocalPort(PORT_VALID); // e.g. 8081
    request.setRemoteAddr(REQUEST_IP); // e.g. 127.0.0.1

then I can call myclass.method(request, response, ...) and check whether some attribute has been correctly set into the request, e.g.

    MyBean attr = (MyBean) request.getAttribute(ATTRIBUTE_NAME));
    // do my Assert.* stuff with 'attr'

MockHttpServletRequest and MockHttpServletResponse work fine where mock(HttpServletRequest.class) fails, for instance where you need to get back the real content of a request attribute which has been previously set within your business logic.

There is no problem at all.

Let's examine these 4 lines of code:

IndexManager indexManager = mock(IndexManager.class);
when(graphDb.index()).thenReturn(indexManager);
when(indexManager.getNodeAutoIndexer()).thenReturn(nodeAutoIndexer);
when(graphDb.index().getRelationshipAutoIndexer()).thenReturn(relAutoIndexer);

The first line creates a mock indexManager.

The second one tells the mock graphDb to return indexManager (the mock created at first line) when the index method is called.

The third one telle the mock indexManager (created at first line) to return nodeAutoIndexer when its getNodeAutoIndexer method is called.

And the last line calls graphDb.index(), which returns the mock indexManager (you told it to do that at line two), and asks this indexManager (which is the mock you created at first line) to return relAutoIndexer when its getRelationshipAutoIndexer method is called.

The last line works only because you told the mock graphDb what to return when its index method is called. If you had not done this before, the mock graphDb.index() method would have returned null and you would have had an NPE.

For Java 8 and above, it's easy:

when(mock.process(Matchers.anyList()));

For Java 7 and below, the compiler needs a bit of help. Use anyListOf(Class<T> clazz):

when(mock.process(Matchers.anyListOf(Bar.class)));

Try Mockito and you will love it!

You can have a look of this library in this blog post, showing 6 simple examples of Mockito usage.

A short example:

@Test
public void iteratorWillReturnHelloWorld(){
    //arrange
    Iterator i = mock(Iterator.class);
    when(i.next()).thenReturn("Hello").thenReturn("World");
    //act
    String result = i.next() + " " + i.next();
    //assert
    assertEquals("Hello World", result);
}

Edit regarding your requirements:

It seems that Mockito runs quite well on Java 1.4 and JUnit 3, as stated in this blog post.

The same example as above, but for Java 1.4:

public void testIteratorWillReturnHelloWorld(){
    //arrange
    Iterator i = Mockito.mock(Iterator.class);
    Mockito.when(i.next()).thenReturn("Hello").thenReturn("World");
    //act
    String result = i.next() + " " + i.next();
    //assert
    assertEquals("Hello World", result);
}

@Mock creates a mock. @InjectMocks creates an instance of the class and injects the mocks that are created with the @Mock (or @Spy) annotations into this instance.

Note you must use @RunWith(MockitoJUnitRunner.class) or Mockito.initMocks(this) to initialize these mocks and inject them (JUnit 4).

With JUnit 5, you must use @ExtendWith(MockitoExtension.class).

@RunWith(MockitoJUnitRunner.class) // JUnit 4
// @ExtendWith(MockitoExtension.class) for JUnit 5
public class SomeManagerTest {

    @InjectMocks
    private SomeManager someManager;

    @Mock
    private SomeDependency someDependency; // this will be injected into someManager
 
     // tests...

}

I know this thread is old, but it's good to add that since 2014 and this pull request, you can use the @PowerMockRunnerDelegate annotation to "delegate" the run context to SpringJUnit4ClassRunner (or any other runner really).

Above code would look like :

@RunWith(PowerMockRunner.class)
@PowerMockRunnerDelegate(SpringJUnit4ClassRunner.class)
@PrepareForTest(X.class);
public class MyTest {

    // Tests goes here
    ...
}

With this annotation, you don't need the PowerMock rule anymore !

TestPropertySource sets a location to a property file. It is even possible to inline specific values:

@TestPropertySource(properties = { "task.enabled = false" })

Try @RunWith(PowerMockRunner.class) instead of @RunWith(MockitoJUnitRunner.class)

Well mockito mocks works by extending the class and overriding the method, which in your case is not possible on A.a(String). If you want this to happen you have to remove the final modifier.

Now assuming A.a(String) is not final, what you ask is completely doable with mockito:

given(mockA.a(anyString()).willAnswer(returnOfB(bInstance));

Answer<String> returnOfB(final B bInstance) {
    return new Answer<String>() {
         public String answer(Invocation invocation) {
             String arg = (String) invocation.getActualArguments()[0];
             return bInstance.b(arg);
         }
    };
}

Please note this answer has been written on a phone and might have typo, or wrong names, though you should get the idea of what should be done to achieve what you want.

Cheers