Showing how we can alter mStarrred by calling onToggleSessionStarred()

SessionDetailPresenter.java

public void onToggleSessionStarred() {

    mStarred = !mStarred;
}

SessionDetailPresenterTests.java

public void testShouldLaunchAddSessionService() {

    //Arrange
    SessionDetailViewTranslator sessionDetailViewTranslator = mock(SessionDetailViewTranslator.class);

    Session session = new Session();
    session.startTimestamp = "1431081943";

    SessionRepositoryManager repositoryManager = new MockSessionRepositoryManager(session);

    ServiceStarter serviceStarter = mock(ServiceStarter.class);

    long calendarId = 0;

    SessionDetailViewPresenter sessionDetailViewPresenter = new SessionDetailViewPresenter(sessionDetailViewTranslator,
                                                                                           repositoryManager,
                                                                                           serviceStarter,
                                                                                           calendarId);
    sessionDetailViewPresenter.onViewCreated(null);
    //****** We call onToggleSessionStarred() to make sure that mStarrred is true
    sessionDetailViewPresenter.onToggleSessionStarred();
    //******
    
    //Act
    sessionDetailViewPresenter.onViewStopped();

    //Assert
    verify(serviceStarter).startAddCalendarSessionService(anyLong(), any(CalendarSession.class));

}