如何等待未来在 Flutter 小部件测试中完成？

Question

我正在尝试执行小部件测试，特别是导航测试。我正在使用 bloc 架构，在 bloc 上设置流触发 bloc 内的一系列事件，从服务器调用获取会话信息（returns 会话信息对象的未来），在成功的服务器调用登录流已设置且小部件具有对此流的流订阅并导航到下一个屏幕。

我正在使用 mockito 来模拟服务器调用并将服务器调用存根到 return 成功响应的未来。问题是当我调用 pumpAndSettle() 时它正在超时，因为它没有等待未来完成和 return 成功响应。

如果我说得不是很清楚，我深表歉意，但这里是示例代码：

login_bloc.dart

class LoginBloc {
  LoginRepository _loginRepository;
  final String searchKeyword = "special-keyword";

  final _urlString = PublishSubject<String>();
  final _isLoggedIn = BehaviorSubject<bool>(seedValue: false);
  final _errorMessage = PublishSubject<String>();

  Observable<bool> get isLoggedIn => _isLoggedIn.stream;
  Observable<String> get isErrorState => _errorMessage.stream;

  LoginBloc({LoginRepository loginRepository})
      : _loginRepository = loginRepository ?? LoginRepository() {
          // Listen on the _urlString stream to call the function which checks for the special keyword and if a match is found make a server call
    _urlString.stream.listen((String url) {
      _authorizationFullService(url);
    });
  }

    // Search for special keyword and if a match is found call the server call function
  void _authorizationFullService(String url) {
    if (url.contains(searchKeyword)) {
      int index = url.indexOf(searchKeyword);
      String result = url.substring(index + searchKeyword.length);
      result = result.trim();
      String decodedUrl = Uri.decodeFull(result);
      if (decodedUrl != null && decodedUrl.length > 0) {
        _fullServiceServerCall(decodedUrl);
      } else {
        _isLoggedIn.sink.add(false);
      }
    }
  }

    // Call server call function from repository which returns a future of the Authorization object
  void _fullServiceServerCall(String decodedUrl) {
    _loginRepository
        .getSession(decodedUrl)
        .then(_handleSuccessAuthorization)
        .catchError(_handleErrorState);
  }

    // Handle success response and set the login stream
  void _handleSuccessAuthorization(Authorization authorization) {
    if (authorization != null && authorization.idnumber != 0) {
      _isLoggedIn.sink.add(true);
    } else {
      _isLoggedIn.sink.add(false);
    }
  }

    // Handle error response and set the error stream
  void _handleErrorState(dynamic error) {
    _isLoggedIn.sink.add(false);
    _errorMessage.sink.add(error.toString());
  }

  void dispose() {
    _urlString.close();
    _isLoggedIn.close();
    _errorMessage.close();
  }
}

widget_test.dart

group('Full Login Navigation test', () {
    LoginRepository mockLoginRepository;
    LoginBloc loginBloc;
    NotificationBloc notificationBloc;
    NavigatorObserver mockNavigatorObserver;
    Authorization _auth;
    String testUrl;

    setUp(() {
      mockLoginRepository = MockLoginRepository();
      _auth = Authorization((auth) => auth
        ..param1 = "foo"
        ..param2 = "bar"
        ..param3 = "foobar"
        ..param4 = "barfoo");
      loginBloc = LoginBloc(loginRepository: mockLoginRepository);
      mockNavigatorObserver = MockNavigatorObserver();
      testUrl = "http://test.test.com";
    });

    Future<Null> _buildFullLoginPage(LoginBloc loginBloc,
        NotificationBloc notificationBloc, WidgetTester tester) async {
      when(mockLoginRepository.getSession(testUrl))
          .thenAnswer((_) => Future.value(_auth));
      await tester.pumpWidget(LoginBlocProvider(
        child: NotificationBlocProvider(
          child: MaterialApp(
            home: LoginFullService(),
            onGenerateRoute: NavigationRoutes.routes,
            navigatorObservers: [mockNavigatorObserver],
          ),
          notificationBloc: notificationBloc,
        ),
        loginBloc: loginBloc,
      ));
      //TODO: Remove casting to dynamic after dart sdk bug fix: https://github.com/dart-lang/mockito/issues/163
      verify(mockNavigatorObserver.didPush(any, any) as dynamic);
      loginBloc.getAuthorization(
          "http://testing.testing.com?search-keyword=http%3A%2F%2Ftest.test.com");
    }

    testWidgets('Navigate to landing page on correct login url',
        (WidgetTester tester) async {
      await _buildFullLoginPage(loginBloc, notificationBloc, tester);
      await tester.pumpAndSettle();
      expect(find.byKey(Key('webview_scaffold')), findsNothing);
      //TODO: Remove casting to dynamic after dart sdk bug fix: https://github.com/dart-lang/mockito/issues/163
      verify(mockNavigatorObserver.didPush(any, any) as dynamic);
    });
});

在运行上，小部件测试 testWidgets 内的 tester.pumpAndSettle() 在 future 完成之前超时。这是错误日志：

══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following assertion was thrown running a test:
pumpAndSettle timed out

When the exception was thrown, this was the stack:
#0      WidgetTester.pumpAndSettle.<anonymous closure> (package:flutter_test/src/widget_tester.dart:299:11)
<asynchronous suspension>
#3      TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:69:41)
#4      WidgetTester.pumpAndSettle (package:flutter_test/src/widget_tester.dart:295:27)
#5      main.<anonymous closure>.<anonymous closure> (file:///Users/ssiddh/Documents/projects/mobile-flutter/test/ui/pages/login/login_full_test.dart:114:20)
<asynchronous suspension>
#6      testWidgets.<anonymous closure>.<anonymous closure> (package:flutter_test/src/widget_tester.dart:72:23)
#7      TestWidgetsFlutterBinding._runTestBody (package:flutter_test/src/binding.dart:555:19)
<asynchronous suspension>
#10     TestWidgetsFlutterBinding._runTest (package:flutter_test/src/binding.dart:539:14)
#11     AutomatedTestWidgetsFlutterBinding.runTest.<anonymous closure> (package:flutter_test/src/binding.dart:883:24)
#17     AutomatedTestWidgetsFlutterBinding.runTest (package:flutter_test/src/binding.dart:880:15)
#18     testWidgets.<anonymous closure> (package:flutter_test/src/widget_tester.dart:71:22)
#19     Declarer.test.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:test/src/backend/declarer.dart:168:27)
<asynchronous suspension>
#20     Invoker.waitForOutstandingCallbacks.<anonymous closure> (package:test/src/backend/invoker.dart:249:15)
<asynchronous suspension>
#25     Invoker.waitForOutstandingCallbacks (package:test/src/backend/invoker.dart:246:5)
#26     Declarer.test.<anonymous closure>.<anonymous closure> (package:test/src/backend/declarer.dart:166:33)
#31     Declarer.test.<anonymous closure> (package:test/src/backend/declarer.dart:165:13)
<asynchronous suspension>
#32     Invoker._onRun.<anonymous closure>.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:test/src/backend/invoker.dart:403:25)
<asynchronous suspension>
#46     _Timer._runTimers (dart:isolate/runtime/libtimer_impl.dart:382:19)
#47     _Timer._handleMessage (dart:isolate/runtime/libtimer_impl.dart:416:5)
#48     _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:169:12)
(elided 30 frames from class _FakeAsync, package dart:async, and package stack_trace)

非常感谢任何形式的帮助或反馈。

Answer 1

尝试用

包装你的测试

testWidgets('Navigate to landing page on correct login url',
    (WidgetTester tester) async {
    await tester.runAsync(() async {

      // test code here

    });
 });

如何等待未来在 Flutter 小部件测试中完成？

How to wait for a future to complete in Flutter widget test?

dart

flutter

flutter-test