### Question:
AdminUserServiceImpl implements AdminUserService { @Override public Response getAllUsers(HttpHeaders headers) { AdminUserServiceImpl.LOGGER.info("[Admin User Service][Get All Users]"); HttpEntity requestEntity = new HttpEntity(headers); ResponseEntity<Response<List<User>>> re = restTemplate.exchange( USER_SERVICE_IP_URI, HttpMethod.GET, requestEntity, new ParameterizedTypeReference<Response<List<User>>>() { }); return re.getBody(); }  @Override Response getAllUsers(HttpHeaders headers); @Override Response deleteUser(String userId, HttpHeaders headers); @Override Response updateUser(UserDto userDto, HttpHeaders headers); @Override Response addUser(UserDto userDto, HttpHeaders headers);  }### Answer:
@Test public void testGetAllUsers() { Response<List<User>> response = new Response<>(); ResponseEntity<Response<List<User>>> re = new ResponseEntity<>(response, HttpStatus.OK); Mockito.when(restTemplate.exchange( "http: HttpMethod.GET, requestEntity, new ParameterizedTypeReference<Response<List<User>>>() { })).thenReturn(re); Response result = adminUserServiceImpl.getAllUsers(headers); Assert.assertEquals(new Response<>(null, null, null), result); }