Flutter-Test: Getting BlocProvider.of() called with a context that does not container Bloc - flutter

Question

I am trying to test my submit button which fires a bloc event onPress.
SubmitButton.dart - Widget
class AuthenticationSubmitButton extends StatefulWidget {
final String buttonLabel;
final TextEditingController _userEmailController;
final TextEditingController _passwordController;
AuthenticationSubmitButton(
this.buttonLabel, this._userEmailController, this._passwordController);
#override
_AuthenticationSubmitButtonState createState() =>
_AuthenticationSubmitButtonState();
}
class _AuthenticationSubmitButtonState
extends State<AuthenticationSubmitButton> {
#override
Widget build(BuildContext context) {
Size screenSize = MediaQuery.of(context).size;
final _authBloc = BlocProvider.of<AuthenticationBloc>(context);
return Container(
child: FlatButton.icon(
height: screenSize.height * 0.07,
minWidth: screenSize.width * 0.5,
padding: EdgeInsets.all(10),
color: Colors.green,
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
onPressed: () {
final email = widget._userEmailController.text.trim();
final password = widget._passwordController.text.trim();
_authBloc.add(UserLoginEvent(email, password));
},
icon: Icon(Icons.keyboard_return_rounded),
label: Text(
widget.buttonLabel,
style: SubmitButtonStyle,
),
),
);
}
}
As you can see I am calling the event UserLoginEvent
authentication_events.dart
#immutable
abstract class AuthenticationEvent {}
/**
* Login Event
* Logout Event
*/
class UserLoginEvent extends AuthenticationEvent {
final String userEmail;
final String userPassword;
UserLoginEvent(this.userEmail, this.userPassword);
}
class ClearLoginEvent extends AuthenticationEvent {
}
And here is my authentication states
authentication_states.dart
#immutable
abstract class AuthenticationState extends Equatable {
}
class AuthenticationInitial extends AuthenticationState {
#override
List<Object> get props => [];
}
/**
* LoginSuccessful
* LoginFailed
* LogoutSuccessful
*/
class LoginSuccessful extends AuthenticationState {
#override
List<Object> get props => [];
}
class LoginError extends AuthenticationState {
#override
List<Object> get props => [];
}
authentication_bloc.dart
class AuthenticationBloc
extends Bloc<AuthenticationEvent, AuthenticationState> {
AuthenticationBloc({this.userRepository}) : super(AuthenticationInitial());
UserRepository userRepository;
#override
Stream<AuthenticationState> mapEventToState(
AuthenticationEvent event,
) async* {
if (event is UserLoginEvent) {
UserRepository repository = userRepository ?? UserRepository();
try {
bool loggedIn = await repository.authenticateUserWithCredentials(
event.userEmail, event.userPassword);
if (loggedIn) {
yield LoginSuccessful();
} else {
yield LoginError();
}
} catch (e) {
yield EmptyLoginCredentials();
}
} else if (event is ClearLoginEvent) {
yield AuthenticationInitial();
}
}
}
And finally my test for submit button
> submit_button_test.dart
class MockAuthBloc extends MockBloc<AuthenticationState>
implements AuthenticationBloc {}
void main() {
TestWidgetsFlutterBinding.ensureInitialized();
MockAuthBloc authBloc = MockAuthBloc();
TextEditingController _userEmailController;
TextEditingController _passwordController;
setUp(() {
_userEmailController = TextEditingController();
_passwordController = TextEditingController();
authBloc = MockAuthBloc();
});
tearDown(() {
_userEmailController.dispose();
_passwordController.dispose();
authBloc?.close();
});
///Provide Material App for giving access to MediaQuery
///Wrap any widget that needs Material widget
Widget buildTestableWidget(Widget widget) {
return MediaQuery(
data: MediaQueryData(),
child: BlocProvider.value(
value: authBloc,
child: MaterialApp(
home: Material(
child: widget,
),
),
),
);
}
group('Testing Submit button |', () {
testWidgets('description', (WidgetTester tester) async {
whenListen(
authBloc,
Stream.fromIterable(<AuthenticationState>[LoginSuccessful()]),
);
await tester.pumpWidget(buildTestableWidget(AuthenticationSubmitButton(
'Submit', _userEmailController, _passwordController)));
final buttonFinder = find.byType(FlatButton);
final button = tester.firstWidget(buttonFinder);
});
});
}
Could you please tell me what am I doing wrong here?
Below is my error
00:03 +19: /home/bhuvanesh/code/kaadhal_host_client/test/screens/Authentication/widgets/submit_button_test.dart: Testing Submit button | description
══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
The following assertion was thrown building AuthenticationSubmitButton(dirty, dependencies:
[MediaQuery], state: _AuthenticationSubmitButtonState#da4f9):
BlocProvider.of() called with a context that does not contain a Bloc/Cubit of type
AuthenticationBloc.
No ancestor could be found starting from the context that was passed to
BlocProvider.of<AuthenticationBloc>().
This can happen if the context you used comes from a widget above the BlocProvider.
The context used was: AuthenticationSubmitButton(dirty, dependencies: [MediaQuery], state:
_AuthenticationSubmitButtonState#da4f9)
The relevant error-causing widget was:
AuthenticationSubmitButton
file:///home/bhuvanesh/code/kaadhal_host_client/test/screens/Authentication/widgets/submit_button_test.dart:57:51
When the exception was thrown, this was the stack:
#0 BlocProvider.of (package:flutter_bloc/src/bloc_provider.dart:121:7)
#1 _AuthenticationSubmitButtonState.build (package:kaadhal_host_client/screens/Authentication/widgets/submit_button.dart:26:36)
#2 StatefulElement.build (package:flutter/src/widgets/framework.dart:4744:28)
#3 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4627:15)
#4 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4800:11)
#5 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
#6 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
#7 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4791:11)
#8 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
... Normal element mounting (174 frames)
#182 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
#183 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6236:32)
... Normal element mounting (267 frames)
#450 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
#451 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
#452 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
#453 _InheritedProviderScopeElement.performRebuild (package:provider/src/inherited_provider.dart:426:11)
#454 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
#455 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
#456 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
... Normal element mounting (7 frames)
#463 SingleChildWidgetElementMixin.mount (package:nested/nested.dart:223:11)
... Normal element mounting (7 frames)
#470 SingleChildWidgetElementMixin.mount (package:nested/nested.dart:223:11)
... Normal element mounting (7 frames)
#477 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
#478 Element.updateChild (package:flutter/src/widgets/framework.dart:3324:20)
#479 RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:1252:16)
#480 RenderObjectToWidgetElement.update (package:flutter/src/widgets/binding.dart:1230:5)
#481 RenderObjectToWidgetElement.performRebuild (package:flutter/src/widgets/binding.dart:1244:7)
#482 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
#483 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2730:33)
#484 AutomatedTestWidgetsFlutterBinding.drawFrame (package:flutter_test/src/binding.dart:1088:18)
#485 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:302:5)
#486 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1117:15)
#487 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1055:9)
#488 AutomatedTestWidgetsFlutterBinding.pump.<anonymous closure> (package:flutter_test/src/binding.dart:961:9)
#491 TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:72:41)
#492 AutomatedTestWidgetsFlutterBinding.pump (package:flutter_test/src/binding.dart:948:27)
#493 WidgetTester.pumpWidget.<anonymous closure> (package:flutter_test/src/widget_tester.dart:524:22)
#496 TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:72:41)
#497 WidgetTester.pumpWidget (package:flutter_test/src/widget_tester.dart:521:27)
#498 main.<anonymous closure>.<anonymous closure> (file:///home/bhuvanesh/code/kaadhal_host_client/test/screens/Authentication/widgets/submit_button_test.dart:57:20)
#499 main.<anonymous closure>.<anonymous closure> (file:///home/bhuvanesh/code/kaadhal_host_client/test/screens/Authentication/widgets/submit_button_test.dart:46:32)
#500 testWidgets.<anonymous closure>.<anonymous closure> (package:flutter_test/src/widget_tester.dart:146:29)
#511 FakeAsync.flushMicrotasks (package:fake_async/fake_async.dart:193:32)
#512 AutomatedTestWidgetsFlutterBinding.runTest.<anonymous closure> (package:flutter_test/src/binding.dart:1189:17)
#513 AutomatedTestWidgetsFlutterBinding.runTest.<anonymous closure> (package:flutter_test/src/binding.dart:1177:35)
(elided 29 frames from dart:async and package:stack_trace)
════════════════════════════════════════════════════════════════════════════════════════════════════
══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following StateError was thrown running a test:
Bad state: No element
When the exception was thrown, this was the stack:
#0 Iterable.first (dart:core/iterable.dart:524:7)
#1 WidgetController.firstWidget (package:flutter_test/src/controller.dart:79:30)
#2 main.<anonymous closure>.<anonymous closure> (file:///home/bhuvanesh/code/kaadhal_host_client/test/screens/Authentication/widgets/submit_button_test.dart:60:29)
<asynchronous suspension>
#3 main.<anonymous closure>.<anonymous closure> (file:///home/bhuvanesh/code/kaadhal_host_client/test/screens/Authentication/widgets/submit_button_test.dart)
#4 testWidgets.<anonymous closure>.<anonymous closure> (package:flutter_test/src/widget_tester.dart:146:29)
<asynchronous suspension>
#5 testWidgets.<anonymous closure>.<anonymous closure> (package:flutter_test/src/widget_tester.dart)
#6 TestWidgetsFlutterBinding._runTestBody (package:flutter_test/src/binding.dart:784:19)
<asynchronous suspension>
#9 TestWidgetsFlutterBinding._runTest (package:flutter_test/src/binding.dart:764:14)
#10 AutomatedTestWidgetsFlutterBinding.runTest.<anonymous closure> (package:flutter_test/src/binding.dart:1173:24)
#11 FakeAsync.run.<anonymous closure>.<anonymous closure> (package:fake_async/fake_async.dart:178:54)
#16 withClock (package:clock/src/default.dart:48:10)
#17 FakeAsync.run.<anonymous closure> (package:fake_async/fake_async.dart:178:22)
#22 FakeAsync.run (package:fake_async/fake_async.dart:178:7)
#23 AutomatedTestWidgetsFlutterBinding.runTest (package:flutter_test/src/binding.dart:1170:15)
#24 testWidgets.<anonymous closure> (package:flutter_test/src/widget_tester.dart:138:24)
#25 Declarer.test.<anonymous closure>.<anonymous closure> (package:test_api/src/backend/declarer.dart:175:19)
<asynchronous suspension>
#26 Declarer.test.<anonymous closure>.<anonymous closure> (package:test_api/src/backend/declarer.dart)
#31 Declarer.test.<anonymous closure> (package:test_api/src/backend/declarer.dart:173:13)
#32 Invoker.waitForOutstandingCallbacks.<anonymous closure> (package:test_api/src/backend/invoker.dart:231:15)
#37 Invoker.waitForOutstandingCallbacks (package:test_api/src/backend/invoker.dart:228:5)
#38 Invoker._onRun.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:test_api/src/backend/invoker.dart:383:17)
<asynchronous suspension>
#39 Invoker._onRun.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:test_api/src/backend/invoker.dart)
#44 Invoker._onRun.<anonymous closure>.<anonymous closure> (package:test_api/src/backend/invoker.dart:370:9)
#45 Invoker._guardIfGuarded (package:test_api/src/backend/invoker.dart:415:15)
#46 Invoker._onRun.<anonymous closure> (package:test_api/src/backend/invoker.dart:369:7)
#53 Invoker._onRun (package:test_api/src/backend/invoker.dart:368:11)
#54 LiveTestController.run (package:test_api/src/backend/live_test_controller.dart:153:11)
#55 RemoteListener._runLiveTest.<anonymous closure> (package:test_api/src/remote_listener.dart:256:16)
#60 RemoteListener._runLiveTest (package:test_api/src/remote_listener.dart:255:5)
#61 RemoteListener._serializeTest.<anonymous closure> (package:test_api/src/remote_listener.dart:208:7)
#79 _GuaranteeSink.add (package:stream_channel/src/guarantee_channel.dart:125:12)
#80 new _MultiChannel.<anonymous closure> (package:stream_channel/src/multi_channel.dart:159:31)
#84 CastStreamSubscription._onData (dart:_internal/async_cast.dart:85:11)
#118 new _WebSocketImpl._fromSocket.<anonymous closure> (dart:_http/websocket_impl.dart:1145:21)
#126 _WebSocketProtocolTransformer._messageFrameEnd (dart:_http/websocket_impl.dart:338:23)
#127 _WebSocketProtocolTransformer.add (dart:_http/websocket_impl.dart:232:46)
#137 _Socket._onData (dart:io-patch/socket_patch.dart:2044:41)
#146 new _RawSocket.<anonymous closure> (dart:io-patch/socket_patch.dart:1580:33)
#147 _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart:1076:14)
(elided 111 frames from dart:async and package:stack_trace)
The test description was:
description
════════════════════════════════════════════════════════════════════════════════════════════════════
══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following message was thrown:
Multiple exceptions (2) were detected during the running of the current test, and at least one was
unexpected.
════════════════════════════════════════════════════════════════════════════════════════════════════
00:03 +19 -1: /home/bhuvanesh/code/kaadhal_host_client/test/screens/Authentication/widgets/submit_button_test.dart: Testing Submit button | description [E]
Test failed. See exception logs above.
The test description was: description

Answer 1

Reasons-
You are coming on this class thought navigator
Your parent is not using same bloc
Solution-
You can use bloc here by passing it to constructor