Mockito. Verify method arguments

I’ve googled about this, but didn’t find anything relevant. I’ve got something like this:

Object obj = getObject();
Mockeable mock= Mockito.mock(Mockeable.class);
Mockito.when(mock.mymethod(obj )).thenReturn(null);

Testeable testableObj = new Testeable();
testableObj.setMockeable(mock);
command.runtestmethod();

Now, I want to verify that mymethod(Object o), which is called inside runtestmethod(), was called with the Object o, not any other. But I always pass the test, whatever I put on the verification, for example, with:

Mockito.verify(mock.mymethod(Mockito.eq(obj)));

or

Mockito.verify(mock.mymethod(Mockito.eq(null)));

or

Mockito.verify(mock.mymethod(Mockito.eq("something_else")));

I always pass the test. How can I accomplish that verification (if possible)?

Thank you.