### Question:
GetUserList extends UseCase<List<User>, Void> { @Override Observable<List<User>> buildUseCaseObservable(Void unused) { return this.userRepository.users(); } @Inject  GetUserList(UserRepository userRepository, ThreadExecutor threadExecutor,
      PostExecutionThread postExecutionThread);   }### Answer:
@Test public void testGetUserListUseCaseObservableHappyCase() { getUserList.buildUseCaseObservable(null); verify(mockUserRepository).users(); verifyNoMoreInteractions(mockUserRepository); verifyZeroInteractions(mockThreadExecutor); verifyZeroInteractions(mockPostExecutionThread); }