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Write tests for Provider
Hiroki Matsue (@macs_6)
May 22th, 2019
Flutter Meetup Tokyo #9
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This talk is about
How to test Provider classes
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What is Provider
Google I/O 2019ͷFlutterʹ͓͚Δ࣮ફతͳstateཧͷൃදͰ
հ͞Εͨύοέʔδ
Pragmatic State Management in Flutter (Google I/O'19)
https://youtu.be/d_m5csmrf7I
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A dependency injection system built with widgets for widgets.
provider is mostly syntax sugar for InheritedWidget, to make
common use-cases straightforward.
https://github.com/rrousselGit/provider
• ΄΅InheritedWidgetͷγϯλοΫεγϡΨʔ
• BLoCΛ͏࣌ʹࣗલͰProvider૬ͷͷΛ࣮͍ͯͨ͠
ͣ
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BLoC͚ʹॻ͍͍ͯͨInheritedWidgetΛͬͨProvider
class CartProvider extends InheritedWidget {
final CartBloc cartBloc;
CartProvider({
Key key,
CartBloc cartBloc,
Widget child,
}) : cartBloc = cartBloc ?? CartBloc(),
super(key: key, child: child);
@override
bool updateShouldNotify(InheritedWidget oldWidget) => true;
static CartBloc of(BuildContext context) =>
(context.inheritFromWidgetOfExactType(CartProvider) as CartProvider)
.cartBloc;
}
final cartBloc = CartProvider.of(context);
https://github.com/filiph/stateexperiments/blob/19c321bbc62ac10855751124e3ea9701e583d6ea/shared/lib/src/bloc/cartprovider.dart
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ProviderύοέʔδΛ͏ͱ͜͏ͳΔ
Provider(
builder: (_) => ExampleBloc(),
dispose: (_, value) => value.dispose(),
child: ExampleBloc(),
);
final bloc = Provider.of(context)
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શ෦BLoCͰॻͭ͘ΓͳΒbloc_providerύοέʔδ
bloc is disposed automatically
https://pub.dev/packages/bloc_provider
BlocProvider(
creator: (_context, _bag) => ExampleBloc(),
child: Example(),
)
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ProviderΛ͏ͱ
• streamRxDartΛΘͣʹෳWidgetؒͷstateΛཧͰ͖
ֶͯशίετ͕͍
• ඞཁʹԠͯ͡BLoCಋೖͰ͖Δ
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How to write tests?
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class Counter with ChangeNotifier {
Counter(
this._number,
);
factory Counter.withInitialValues({
int number = 0,
}) {
return Counter(number);
}
int _number;
int get number => _number;
void increment() {
_number++;
notifyListeners();
}
}
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notifyListeners()Λແࢹ͢ΔͳΒ
test('increment', () {
final counter = Counter.withInitialValues();
expect(counter.number, 0);
counter.increment();
expect(counter.number, 1);
});
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֤छύοέʔδͷςετͰtestWidgetsΛ͍ͬͯΔ
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UIςετͱͯ͠
widgetΛςετ͚ʹॳظԽ͢Δ
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testWidgets("increment", (tester) async {
final key = GlobalKey();
await tester.pumpWidget(
ChangeNotifierProvider(
builder: (context) => Counter.withInitialValues(),
child: MaterialApp(
home: Consumer(
builder: (context, counter, child) => FlatButton(
key: key,
onPressed: () => counter.increment(),
child: Text(counter.number.toString())),
),
),
),
);
expect(find.text('0'), findsOneWidget);
expect(find.text('1'), findsNothing);
await tester.tap(find.byKey(key));
await tester.pumpAndSettle();
expect(find.text('0'), findsNothing);
expect(find.text('1'), findsOneWidget);
});
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֤छύοέʔδͷςετͰݟΒΕΔ
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͍ճ͢widgetΛอଘ͓ͯ͘͠
final tree = ChangeNotifierProvider(
builder: (context) => Counter.withInitialValues(),
child: MaterialApp(
home: Consumer(
builder: (context, counter, child) => FlatButton(
key: key,
onPressed: () => counter.increment(),
child: Text(counter.number.toString())),
),
),
);
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ʹରͯ͠ݕূΛߦ͏
testWidgets("increment", (tester) async {
final key = GlobalKey();
int number;
await tester.pumpWidget(
ChangeNotifierProvider(
builder: (context) => Counter.withInitialValues(),
child: MaterialApp(
home: Consumer(builder: (context, counter, child) {
number = counter.number;
return FlatButton(
key: key,
onPressed: () => counter.increment(),
child: Container(),
);
}),
),
),
);
});
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notifierΛcontext͔Βऔಘͯ͠ݕূ͢Δ
testWidgets('works with MultiProvider', (tester) async {
final key = GlobalKey();
var notifier = ChangeNotifier();
await tester.pumpWidget(MultiProvider(
providers: [
ChangeNotifierProvider.value(notifier: notifier),
],
child: Container(key: key),
));
expect(Provider.of(key.currentContext), notifier);
});
https://github.com/rrousselGit/provider/blob/fe778651565f7563dc4a1b2afb513119c5424761/test/changenotifierprovider_test.dart#L11-
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·ͱΊ
• testWidgets Λͬͯςετॻ͘
• ֤छύοέʔδΛݟΔͱςετͷهड़ΛݮΒ͕͢৭ʑݟ
ΒΕΔ
• ରͷwidgetΛ͍ճ͢
• มʹೖΕͯݕূ͢Δ
• notifierΛऔಘ͢Δ
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References
• Developer Questͷςετ: https://github.com/2d-inc/
developerquest/blob/master/test/worldtest.dart
• Providerύοέʔδͷςετ: https://github.com/
rrousselGit/provider/blob/
fe778651565f7563dc4a1b2afb513119c5424761/test/
changenotifierprovider_test.dart
• FlutterຊମͷChangeNotifierςετ: https://github.com/
flutter/flutter/blob/
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Thanks