public class Simple_Mock{
	class Mission{
		public Mission(){
		}
		public void complete(int arg){
		 // code
		}
		public boolean isComplete(){
			//code
			return false;
		}
	}


	//void answer
	@Test
	public void mock_Mission_test{
		Mission mission_mock = mock(Mission.class);
		doAnswer(new Answer<Void>() {
					public Void answer(InvocationOnMock invocation) {
						when(mission_mock.isCompleted()).thenReturn(true);

						// get arguments from the innvocation if the method is called with args.
						// The doAnswer is how to mock a method LOL
						Integer arg = invocation.getArguments()[0];
						System.out.println(arg);
						return null;
					}
				}).when(mission_mock).complete(0);

		task_mock.complete(0);
		assertTrue(mission_mock.isCompleted());
	}

}