@Test
public void removeBookmarkOfUserRemovesBookmark() {

    // given
    given(userMock.getId()).willReturn(USER_ID);
    given(userRepository.existsByIdAndBookmarksContaining(USER_ID, projectMock)).willReturn(true);
    // when
    bookmarkService.removeBookmarkOfUser(userMock, projectMock);
    // then
    verify(userMock).removeBookmark(projectMock);
    verify(userRepository).save(userMock);
}