### Question:
UserApi { public CompletableFuture<String> loginUser(String username, String password) throws ApiException { try { HttpRequest.Builder localVarRequestBuilder = loginUserRequestBuilder(username, password); return memberVarHttpClient.sendAsync( localVarRequestBuilder.build(), HttpResponse.BodyHandlers.ofString()).thenComposeAsync(localVarResponse -> { if (localVarResponse.statusCode()/ 100 != 2) { return CompletableFuture.failedFuture(getApiException("loginUser", localVarResponse)); } try { return CompletableFuture.completedFuture( memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<String>() {}) ); } catch (IOException e) { return CompletableFuture.failedFuture(new ApiException(e)); } }); } catch (ApiException e) { return CompletableFuture.failedFuture(e); } } UserApi();  UserApi(ApiClient apiClient); CompletableFuture<Void> createUser(User body); CompletableFuture<ApiResponse<Void>> createUserWithHttpInfo(User body); CompletableFuture<Void> createUsersWithArrayInput(List<User> body); CompletableFuture<ApiResponse<Void>> createUsersWithArrayInputWithHttpInfo(List<User> body); CompletableFuture<Void> createUsersWithListInput(List<User> body); CompletableFuture<ApiResponse<Void>> createUsersWithListInputWithHttpInfo(List<User> body); CompletableFuture<Void> deleteUser(String username); CompletableFuture<ApiResponse<Void>> deleteUserWithHttpInfo(String username); CompletableFuture<User> getUserByName(String username); CompletableFuture<ApiResponse<User>> getUserByNameWithHttpInfo(String username); CompletableFuture<String> loginUser(String username, String password); CompletableFuture<ApiResponse<String>> loginUserWithHttpInfo(String username, String password); CompletableFuture<Void> logoutUser(); CompletableFuture<ApiResponse<Void>> logoutUserWithHttpInfo(); CompletableFuture<Void> updateUser(String username, User body); CompletableFuture<ApiResponse<Void>> updateUserWithHttpInfo(String username, User body);  }### Answer:
@Test public void loginUserTest() throws ApiException { String username = null; String password = null; CompletableFuture<String> response = api.loginUser(username, password); }