How to use getName method of org.mockito.internal.creation.DelegatingMethod class

add <absolute-ordering /> tag to your web.xml just under the <display-name> tag. should work.

You can use PowerMockito

See the example:

Second second = Mockito.mock(Second.class);
whenNew(Second.class).withNoArguments().thenReturn(second);

But re-factoring is better decision.

I think you need to pass the Matcher to the jsonPath method. For example.

.andExpect(jsonPath("$.version", is("0.1")))

References:
http://docs.spring.io/spring/docs/3.2.x/javadoc-api/org/springframework/test/web/servlet/result/MockMvcResultMatchers.html#jsonPath(java.lang.String,%20org.hamcrest.Matcher)

https://www.petrikainulainen.net/programming/spring-framework/integration-testing-of-spring-mvc-applications-write-clean-assertions-with-jsonpath/

SpringMVC/ mockMVC/ jsonpath compare list of strings

To test the lambdas behavior, the underlayingApi has to be mocked where the lambda is invoked via the InvoactionOnMock object like this.

    `when`(underlayingApi.post(eq("some/rest/url"),
                               any())).thenAnswer {
        val argument = it.arguments[1]
        val completion = argument as ((rawResult: String?, exception: Exception?) -> Unit)
        completion.invoke("result", null)
    }

This leads to the invocation of the callback within the object under test. Now to check if the callback out of the object under test is working verify it like that.

    objUnderTest.loadData(id,
                          { json, exception ->
                              assert....
                          })

It is very likely that the Runnable hasn't been executed yet by the asyncTaskExecutor when you verify the invocation, resulting in a verification error in your unit test.

The best way to fix this is to join on the generated thread and wait for execution before verifying the invocations.

If you cannot get the instance of the thread, a possible work around is to mock the asyncTaskExecutor and implement it so it will execute the runnable directly.

private ExecutorService executor;

@Before
public void setup() {
    executor = mock(ExecutorService.class);
    implementAsDirectExecutor(executor);
}

protected void implementAsDirectExecutor(ExecutorService executor) {
    doAnswer(new Answer<Object>() {
        public Object answer(InvocationOnMock invocation) throws Exception {
            ((Runnable) invocation.getArguments()[0]).run();
            return null;
        }
    }).when(executor).submit(any(Runnable.class));
}

You can also use the non-type safe method doReturn for this purpose,

@Test
public void testMockitoWithGenerics()
{
    DummyClass dummyClass = Mockito.mock(DummyClass.class);
    List<? extends Number> someList = new ArrayList<Integer>();

    Mockito.doReturn(someList).when(dummyClass).dummyMethod();

    Assert.assertEquals(someList, dummyClass.dummyMethod());
}

as discussed on Mockito's google group.

While this is simpler than thenAnswer, again note that it is not type safe. If you're concerned about type safety, millhouse's answer is correct.

Additional Details

To be clear, here's the observed compiler error,

The method thenReturn(List<capture#1-of ? extends Number>) in the type OngoingStubbing<List<capture#1-of ? extends Number>> is not applicable for the arguments (List<capture#2-of ? extends Number>)

I believe the compiler has assigned the first wildcard type during the when call and then cannot confirm that the second wildcard type in the thenReturn call is the same.

It looks like thenAnswer doesn't run into this issue because it accepts a wildcard type while thenReturn takes a non-wildcard type, which must be captured. From Mockito's OngoingStubbing,

OngoingStubbing<T> thenAnswer(Answer<?> answer);
OngoingStubbing<T> thenReturn(T value);

Further reading has led me to try using ArgumentCaptors and the following works, although much more verbose than I would like.

ArgumentCaptor<String> argument = ArgumentCaptor.forClass(String.class);

verify(errors, atLeastOnce()).add(argument.capture(), any(ActionMessage.class));

List<String> values = argument.getAllValues();

assertTrue(values.contains("exception.message"));
assertTrue(values.contains("exception.detail"));

I would recommend approach #1, but would use Spring for dependency injection rather than instantiating DAOs directly.

This way, for unit testing the client code, you can substitue mock DAOs, and verify that the correct DAOs are invoked with the appropriate arguments. (Mockito is useful here.)

If you use static methods, then unit testing is much more difficult, since static methods cannot be overridden.

My apologies to the previous respondents; but in my opinion, using an Answer flies a little in the face of one of the basic ideas of Mockito, namely that stubbing and verifying are two completely separate processes. Mockito has features for stubbing and features for verification, and the makers of Mockito have made an effort to keep the two separate. Answers are intended for stubbing; and whereas there are a few cases where an Answer is the best way to verify, I don't believe this is one of them.

I would use an ArgumentCaptor instead of an Answer. I would write a method like this in the test class, then call it with "Hello world" as the argument. Note that I haven't tested this, so it may contain typos.

private void verifyCharactersWritten( String expected ){
    ArgumentCaptor<Character> captor = ArgumentCaptor.forClass( Character.class ); 
    verify( mockWriter, times( expected.length())).write( captor.capture());
    assertEquals( Arrays.asList( expected.toCharArray()), captor.getAllValues());
}

Hope this helps.