### Question:
UserApi { public Mono<String> loginUser(String username, String password) throws WebClientResponseException { Object postBody = null; if (username == null) { throw new WebClientResponseException("Missing the required parameter 'username' when calling loginUser", HttpStatus.BAD_REQUEST.value(), HttpStatus.BAD_REQUEST.getReasonPhrase(), null, null, null); } if (password == null) { throw new WebClientResponseException("Missing the required parameter 'password' when calling loginUser", HttpStatus.BAD_REQUEST.value(), HttpStatus.BAD_REQUEST.getReasonPhrase(), null, null, null); } final Map<String, Object> pathParams = new HashMap<String, Object>(); final MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<String, String>(); final HttpHeaders headerParams = new HttpHeaders(); final MultiValueMap<String, String> cookieParams = new LinkedMultiValueMap<String, String>(); final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<String, Object>(); queryParams.putAll(apiClient.parameterToMultiValueMap(null, "username", username)); queryParams.putAll(apiClient.parameterToMultiValueMap(null, "password", password)); final String[] localVarAccepts = { "application/xml", "application/json" }; final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts); final String[] localVarContentTypes = { }; final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes); String[] localVarAuthNames = new String[] { }; ParameterizedTypeReference<String> localVarReturnType = new ParameterizedTypeReference<String>() {}; return apiClient.invokeAPI("/user/login", HttpMethod.GET, pathParams, queryParams, postBody, headerParams, cookieParams, formParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType); } UserApi(); @Autowired  UserApi(ApiClient apiClient); ApiClient getApiClient(); void setApiClient(ApiClient apiClient); Mono<Void> createUser(User body); Mono<Void> createUsersWithArrayInput(List<User> body); Mono<Void> createUsersWithListInput(List<User> body); Mono<Void> deleteUser(String username); Mono<User> getUserByName(String username); Mono<String> loginUser(String username, String password); Mono<Void> logoutUser(); Mono<Void> updateUser(String username, User body);  }### Answer:
@Test public void loginUserTest() { String username = null; String password = null; String response = api.loginUser(username, password).block(); }