@Test
public void listContributors() throws Exception {

    TestSubscriber<List<UserEntity>> subscriber = TestSubscriber.create();
    repositoryDataSource.listContributors("TellH", "GitClub", 1).subscribe(subscriber);
    List<UserEntity> userList = subscriber.getOnNextEvents().get(0);
    assertNotNull(userList);
    System.out.println(userList.toString());
}