@Test
 public void testReadUserById() throws Exception {
   User randomUser = userManagerService.getRandomUser();
   UserPK userPK = new UserPK(randomUser.getId(), HistoricalCrudDataManagerImpl.END_TS);
   User user = userManagerService.getUser(userPK);
   Assert.assertNotNull(user);
   System.out.println(user);
 }
 @Test
 public void testUpdateUser() throws Exception {
   User randomUser = userManagerService.getRandomUser();
   String newPw = "" + System.currentTimeMillis();
   // String newPw = randomUser.getPassword(); // test with no change in password by uncommenting
   // this line.
   randomUser.setPassword(newPw);
   userManagerService.updateUser(randomUser);
   User updatedUser = userManagerService.getUser(new UserPK(randomUser.getId()));
   Assert.assertEquals(newPw, updatedUser.getPassword());
 }