@Test
public void initializeThumbnailPhotosOnlyInitializeNonInitialized() {

    // given
    var otherUserId = "other-user";
    var expectedId = 1337L;
    var expectedFirstName = "First";
    var expectedLastName = "Last";
    var expectedMail = "mail@test.de";
    var expectedLob = "LoB Test";
    var expectedThumbnail = new byte[] {2, 1, 32, 4, 7, 42};
    var uninitialized = new UserData(userMock, expectedFirstName, expectedLastName, expectedMail, expectedLob)
            .setId(expectedId)
            .setPictureInitialized(false);
    var expectedInitialized = new UserData(userMock, expectedFirstName, expectedLastName, expectedMail, expectedLob, expectedThumbnail)
            .setId(expectedId)
            .setPictureInitialized(true);
    given(userDataMock.isPictureInitialized()).willReturn(true);
    given(userDataMock.getUser()).willReturn(otherUserMock);
    given(otherUserMock.getId()).willReturn(otherUserId);
    given(ldapAdapterMock.getThumbnailPhotos(List.of(USER_ID))).willReturn(Map.of(
            USER_ID, expectedThumbnail
    ));
    given(userDataRepoMock.saveAll(List.of(expectedInitialized))).willReturn(List.of(expectedInitialized));
    // when
    var actualInitialized = repoUserService.initializeThumbnailPhotos(List.of(uninitialized, userDataMock));
    // then
    assertThat(actualInitialized).containsExactly(expectedInitialized, userDataMock);
    verify(ldapAdapterMock).getThumbnailPhotos(List.of(USER_ID));
    verify(userDataRepoMock).saveAll(List.of(expectedInitialized));
}