@Test
public void loginCallsInteractor()
        throws Exception {

    // given
    loginPresenter.username = "Hello";
    loginPresenter.password = "World";
    loginPresenter.loginInteractor = loginInteractor;
    PresenterUtils.setView(loginPresenter, viewContract);
    Single<Boolean> task = Mockito.mock(Single.class);
    Mockito.when(loginInteractor.login("Hello", "World")).thenReturn(task);
    // when
    loginPresenter.login();
    // then
    Mockito.verify(loginInteractor).login("Hello", "World");
}