如何在小部件测试中使用 get_it（flutter 依赖注入）？

Question

当我在项目中使用依赖注入时，我的小部件测试失败。

我的错误如下：

Testing started at 10:07 AM ...
C:\src\flutter\bin\flutter.bat --no-color test --machine --plain-name "Exist FloatingActionButton" test\features\announcement\presentation\widgets_test\announcement_widget_test.dart
══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞══════════════════════'═════════════════════════════════════
The following assertion was thrown building _BodyBuilder:
No type AnnouncementBloc is registered inside GetIt.
Did you forget to pass an instance name?
(Did you accidentally do GetIt sl=GetIt.instance(); instead of GetIt sl=GetIt.instance;did you
forget to register it?)
'package:get_it/get_it_impl.dart':
Failed assertion: line 251 pos 14: 'instanceFactory != null'

The relevant error-causing widget was:
Scaffold
file:///C:/Projects/niaz-flutter/lib/features/announcement/presentation/pages/announcements_page.dart:15:12

When the exception was thrown, this was the stack:
#2 _GetItImplementation._findFactoryByNameOrType (package:get_it/get_it_impl.dart:251:14)
#3 _GetItImplementation.get (package:get_it/get_it_impl.dart:263:27)
#4 _GetItImplementation.call (package:get_it/get_it_impl.dart:288:12)
#5 new _AnnouncementsWidgetState (package:niaz/features/announcement/presentation/widgets/announcements_widget.dart:22:19)
#6 AnnouncementsWidget.createState (package:niaz/features/announcement/presentation/widgets/announcements_widget.dart:18:46)
#7 new StatefulElement (package:flutter/src/widgets/framework.dart:4600:25)
#8 StatefulWidget.createElement (package:flutter/src/widgets/framework.dart:896:38)
... Normal element mounting (19 frames)
#27 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3455:14)
#28 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5956:32)
... Normal element mounting (193 frames)
#221 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3455:14)
#222 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5956:32)
... Normal element mounting (255 frames)
#477 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3455:14)
#478 Element.updateChild (package:flutter/src/widgets/framework.dart:3220:20)
#479 RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:1132:16)
#480 RenderObjectToWidgetElement.update (package:flutter/src/widgets/binding.dart:1110:5)
#481 RenderObjectToWidgetElement.performRebuild (package:flutter/src/widgets/binding.dart:1124:7)
#482 Element.rebuild (package:flutter/src/widgets/framework.dart:4227:5)
#483 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2632:33)
#484 AutomatedTestWidgetsFlutterBinding.drawFrame (package:flutter_test/src/binding.dart:1016:18)
#485 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:284:5)
#486 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1113:15)
#487 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1052:9)
#488 AutomatedTestWidgetsFlutterBinding.pump. (package:flutter_test/src/binding.dart:889:9)
#491 TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:72:41)
#492 AutomatedTestWidgetsFlutterBinding.pump (package:flutter_test/src/binding.dart:876:27)
#493 WidgetTester.pumpWidget. (package:flutter_test/src/widget_tester.dart:462:22)
#496 TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:72:41)
#497 WidgetTester.pumpWidget (package:flutter_test/src/widget_tester.dart:459:27)
#498 main. (file:///C:/Projects/niaz-flutter/test/features/announcement/presentation/widgets_test/announcement_widget_test.dart:15:18)
#499 main. (file:///C:/Projects/niaz-flutter/test/features/announcement/presentation/widgets_test/announcement_widget_test.dart:14:45)
#500 testWidgets.. (package:flutter_test/src/widget_tester.dart:144:29)
#511 FakeAsync.flushMicrotasks (package:fake_async/fake_async.dart:192:32)
#512 AutomatedTestWidgetsFlutterBinding.runTest. (package:flutter_test/src/binding.dart:1109:17)
#513 AutomatedTestWidgetsFlutterBinding.runTest. (package:flutter_test/src/binding.dart:1097:35)
(elided 31 frames from class _AssertionError, dart:async, and package:stack_trace)

════════════════════════════════════════════════════════════════════════════════════════════════════

Test failed. See exception logs above.

测试描述为：Exist FloatingActionButton

Answer 1

在GetIt 中没有注册类型AnnouncementBloc。您是否忘记传递实例名称？

您需要先在测试模式下使用[getIt.registerFactory< AnnouncementBloc >(() => AnnouncementBloc());]。

例如，我在我的应用程序中使用了服务定位器模式，并将getIt 那里的所有块和存储库，所以我在serviceLocator 中设置了一个布尔型[testing] 像：

Future<void> serviceLocator({bool testing = false}) async {
    if (testing){
        // unit/widget/bloc test
        getIt.registerFactory<AccountBloc>(() => AccountBloc(accountRepository: getIt()));
        getIt.registerFactory<AccountRepository>(() => AccountRepositoryMock());

    } else {
        // run app
        getIt.registerFactory<AccountBloc>(() => AccountBloc(accountRepository: getIt()));
        getIt.registerFactory<AccountRepository>(() => AccountRepositoryFactory(dioProvider: getIt()));
    }
}

另外，您需要在测试文件中将 [testing] 指定为 true，例如：

void main(){
  serviceLocator(testing: true);

  testWidgets('try widget test', (WidgetTester tester) async {
     .
     .
     .
    });
}

Answer 2

你的问题很不清楚（我想看看你的测试代码），但我想我可以帮助你。

您可以在setUp() 或setUpAll() 中设置GetIt.instance 并注册您的模拟BLoC，如下所示：

class MockMyBloc extends MockBloc<MyStates> implements MyBloc {}

void main() {

    MyBloc bloc;
    MockMyBloc mockMyBloc;
   
    setUp(() {
        mockMyBloc = MockMyBloc();
        final dependency_injection = GetIt.instance;
        dependency_injection.registerFactory<MyBloc>(() => mockMyBloc);

        bloc = dependency_injection<MyBloc>();
    });

    //tests
}

Answer 3

这取决于您最初在项目中设置get_it 的方式。

为了解决我的设置问题，我只是在测试文件的setUpAll 方法中调用了注册我的依赖项的方法。

所以我在 lib 文件夹的根目录中有一个文件来注册我的依赖项：

final getIt = GetIt.instance;

void setupDependencyInjection() {
  GetIt.instance.registerSingleton<SomeServiceInterface>(SomeService());
}
 

setupDependencyInjection 方法在 main.dart 文件中的 runApp app 方法之前调用。

对于测试，您只需在测试文件的 setUpAll 方法中调用相同的方法。

void main() {
  setUpAll(() {
    setupDependencyInjection();
  });


  testWidgets('Some test description', (WidgetTester tester) async {

    final widget = TestWidget();

    await tester.pumpWidget(widget);
  });
}