### Question:
RestUserDetailsService implements UserDetailsManager { @Override public void createUser(UserDetails userDetails) { restTemplate.postForLocation("/", userDetails); } RestUserDetailsService(RestTemplateBuilder builder,
                                  @Value("${app.service.url.users}") String rootUri); @Override UserDetails loadUserByUsername(String username); @Override void createUser(UserDetails userDetails); @Override void updateUser(UserDetails userDetails); @Override void deleteUser(String username); @Override void changePassword(String username, String password); @Override boolean userExists(String username);  }### Answer:
@Test public void testCreateUser() throws Exception { server.expect(requestTo("/")).andExpect(method(POST)) .andRespond(withStatus(HttpStatus.CREATED)); UserDetails user = new User(USERNAME, PASSWORD, ENABLED); service.createUser(user); server.verify(); }