    @Test
    public void test_getAllAdmins() {

        Entry<Object, Object> entry = new SimpleEntry<>(USERNAME, USERDATA);
        Set<Entry<Object, Object>> set = new HashSet<>();
        set.add(entry);
        Mockito.when(users.entrySet()).thenReturn(set);

        List<UserDetails> admins = adminDetailsServiceToTest.getAllAdmins();
        Assert.assertTrue(admins.size() == 1);
        Assert.assertEquals(USERNAME, admins.get(0).getUsername());
        Assert.assertEquals("", admins.get(0).getPassword());
        Assert.assertEquals(
                GilesGrantedAuthority.ROLE_ADMIN,
                ((GilesGrantedAuthority)admins.get(0).getAuthorities().toArray()[0]).getAuthority());
    }