How to use get_it (flutter dependency injection) in the widget test?

When I use dependency injections in a project, my widget tests fails.

My error is as follows:

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.

The test description was: Exist FloatingActionButton

First Initalize your dependency container and then unregister previously registered dependency and then register with mockdependency

import 'package:your_app/injection_container.dart' as di;  //import your depencency/ioc container

class MockMyCubit extends MockCubit<MyState> implements MyCubit {}

void main() {
  late MockMyCubit mockMyCubit;

   setUpAll(() async {
      di.init();   //to register your dependencies
      mockMyCubit = MockMyCubit(); //create instance of mockCubit
      await di.sl.unregister<MyCubit>();//unregister previously registered cubit
      di.sl.registerFactory<MyCubit>(() => mockMyCubit); //register mockCubit
    });

  tearDownAll(() {
  di.sl.reset(dispose: true);
  });

  testWidgets('', (teser) async {
 //testyour widget here
 }
}