How to use should_validate_mock method of org.mockito.internal.util.ObjectMethodsGuruTest class

This should work

import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.verify;

verify(bar).DoStuff(any(Foo[].class));

Perhaps it is too late for your question. I met it today and found the solution at the following url. Basically, you need to specify your argument type like.

whenNew(MimeMessage.class).**withParameterTypes(MyParameterType.class)**.withArguments(isA(MyParameter.class)).thenReturn(mimeMessageMock); 

http://groups.google.com/group/powermock/msg/347f6ef1fb34d946?pli=1

Hope it can help you. :)

You should use PowerMock if you want Foo to return the same instance of Bar when you call doSomething method on any instance of Foo. Here's an example:

@RunWith(PowerMockRunner.class)
@PrepareForTest(Foo.class)
public class FooMockAllInstanceTest {

    @Test
    public void testMockInstanceofObjectCreation() throws Exception {
        Bar mockBar = PowerMockito.mock(Bar.class);
        when(mockBar.sayHello()).thenReturn("Hi John!");
        PowerMockito.whenNew(Bar.class)
                .withNoArguments()
                .thenReturn(mockBar);

        Foo myFooOne = new Foo();
        assertEquals(mockBar,  myFooOne.doSomething("Jane"));

        Foo myFooTwo = new Foo();
        assertEquals(mockBar,  myFooTwo.doSomething("Sarah"));

        Baz bazOne = new Baz();
        assertEquals(mockBar, bazOne.doSomething("Sam"));

        Baz bazTwo = new Baz();
        assertEquals(mockBar, bazTwo.doSomething("Nina"));
    }
}

This example will return the same Bar object even when Baz is called. Here's the Baz class,

public class Baz {

    public Bar doSomething(String name) {
        Foo foo = new Foo();
        return foo.doSomething(name);
    }
}

Update 2

There's another slightly better way to test with PowerMock. Here it's,

@Test
public void testStubbingMethod() throws Exception {
    Bar mockBar = PowerMockito.mock(Bar.class);
    when(mockBar.sayHello()).thenReturn("Hi John!");

    PowerMockito.stub(PowerMockito.method(Foo.class, "doSomething",
            String.class)).toReturn(mockBar);

    Foo myFooOne = new Foo();
    assertEquals(mockBar, myFooOne.doSomething("Jane"));

    Foo myFooTwo = new Foo();
    assertEquals(mockBar, myFooTwo.doSomething("Sarah"));

    Baz bazOne = new Baz();
    assertEquals(mockBar, bazOne.doSomething("Sam"));

    Baz bazTwo = new Baz();
    assertEquals(mockBar, bazTwo.doSomething("Nina"));
}

According to the Mockito documentation, you can make a mock serializable:

List serializableMock = mock(List.class, withSettings().serializable());

The reason why IsNonEmpty.matches() gets called on the second line of stubbing is that the Mockito.argThat(new IsEmpty()) returns null, which is then passed to mockHTable.get(). This call has to be checked against the earlier stubbing, to see whether it's a match; and that means calling IsNonEmpty.matches().

I'm not sure why this makes your test fail - it's hard to tell without seeing all of the code.

But, I would seriously recommend using doReturn...when instead of when...thenReturn whenever you have to stub the same mock more than once. You won't encounter issues like this if you do. In fact, I prefer to use doReturn...when in preference to when...thenReturn always (and similarly doThrow and doAnswer), although most people prefer when...thenReturn.

Re-writing one of your stubbing lines with the doReturn...when syntax looks like the following. The other is similar.

Mockito.doReturn(dbResult).when(mockHTable).get(Mockito.argThat(new IsNonEmpty()));  

Lastly, a plea, on behalf of the Mockito development team (of which I am a member). If you think there is a bug in Mockito here - and from your description, I think there may well be - please EITHER

• send a message to the Mockito mailing group (mockito@googlegroups.com) OR
• raise an issue on the Mockito issues list (http://code.google.com/p/mockito/issues/list).

It's useful to the Mockito team if you can actually post a complete example, rather than just what you think the key lines are - sometimes the cause of a Mockito problem is in quite an unexpected place.

Take a look at the Mockito API docs. As the linked document mentions (Point # 12) you can use any of the doThrow(),doAnswer(),doNothing(),doReturn() family of methods from Mockito framework to mock void methods.

For example,

Mockito.doThrow(new Exception()).when(instance).methodName();

or if you want to combine it with follow-up behavior,

Mockito.doThrow(new Exception()).doNothing().when(instance).methodName();

Presuming that you are looking at mocking the setter setState(String s) in the class World below is the code uses doAnswer method to mock the setState.

World mockWorld = mock(World.class); 
doAnswer(new Answer<Void>() {
    public Void answer(InvocationOnMock invocation) {
      Object[] args = invocation.getArguments();
      System.out.println("called with arguments: " + Arrays.toString(args));
      return null;
    }
}).when(mockWorld).setState(anyString());

@Mock
JdbcTemplate jdbctemplate;

@Test
public void testRun(){
when(jdbctemplate.queryForObject(anyString(),eq(String.class),anyObject()).thenReturn("data");
}

Mocking static methods is available since Mockito 3.4.

See pull request: Mockito #1013: Defines and implements API for static mocking.

Please note that the fact that this feature is available is not equivalent with recommendation to use it. It is aimed at legacy apps where you cannot refactor the source code.

Having said that:

Test when static method takes no arguments:

try (MockedStatic<SomePublicClass> dummyStatic = Mockito.mockStatic(SomePublicClass.class)) {
    dummyStatic.when(SomePublicClass::myPublicStaticFunc)
               .thenReturn(5);
    // when
    System.out.println(SomePublicClass.myPublicStaticFunc());
    //then
    dummyStatic.verify(
            times(1),
            SomePublicClass::myPublicStaticFunc
    );
}

Test when static methods takes arguments:

try (MockedStatic<SomePublicClass> dummyStatic = Mockito.mockStatic(SomePublicClass.class)) {
    dummyStatic.when(() -> SomePublicClass.myPublicStaticFunc(anyInt()))
               .thenReturn(5);
    // when
    System.out.println(SomePublicClass.myPublicStaticFunc(7));
    //then
    dummyStatic.verify(
            times(1), 
            () -> SomePublicClass.myPublicStaticFunc(anyInt())
    );
}

If you are willing to use Spring test util, it's fairly easy with org.springframework.test.util.ReflectionTestUtils.

MappingDef mappingDef = Mappers.getMapper(MappingDef.class);
MappingUtils mappingUtils = Mappers.getMapper(MappingUtils.class);

...

// Somewhere appropriate
@Before
void before() {
    ReflectionTestUtils.setField(
        mappingDef,
        "mappingUtils",
        mappingUtils
    )
}