@Test
public void testJoinIds() {

    assertEquals("", UkelonnServiceProvider.joinIds(null).toString());
    assertEquals("", UkelonnServiceProvider.joinIds(Collections.emptyList()).toString());
    assertEquals("1", UkelonnServiceProvider.joinIds(Arrays.asList(1)).toString());
    assertEquals("1, 2", UkelonnServiceProvider.joinIds(Arrays.asList(1, 2)).toString());
    assertEquals("1, 2, 3, 4", UkelonnServiceProvider.joinIds(Arrays.asList(1, 2, 3, 4)).toString());
    UserManagementServiceProvider useradmin = mock(UserManagementServiceProvider.class);
    no.priv.bang.osgiservice.users.User user = new no.priv.bang.osgiservice.users.User(1, "jad", "jad@gmail.com", "Jane", "Doe");
    when(useradmin.getUser(anyString())).thenReturn(user);
    UkelonnServiceProvider ukelonn = getUkelonnServiceSingleton();
    ukelonn.setUserAdmin(useradmin);
    Account account = ukelonn.getAccount("jad");
    List<Integer> jobs = ukelonn.getJobs(account.getAccountId()).stream().map(Transaction::getId).collect(Collectors.toList());
    assertEquals("31, 33, 34, 35, 37, 38, 39, 41, 42, 43", UkelonnServiceProvider.joinIds(jobs).toString());
}