blob: cb3f6a8ab576c17c1a6cc4b3113de9fd090ee3c4 [file] [log] [blame]
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// @dart = 2.8
import 'package:flutter/foundation.dart';
import 'package:flutter_test/flutter_test.dart';
class TestNotifier extends ChangeNotifier {
void notify() {
notifyListeners();
}
bool get isListenedTo => hasListeners;
}
class HasListenersTester<T> extends ValueNotifier<T> {
HasListenersTester(T value) : super(value);
bool get testHasListeners => hasListeners;
}
class A {
bool result = false;
void test() { result = true; }
}
class B extends A with ChangeNotifier {
@override
void test() {
notifyListeners();
super.test();
}
}
void main() {
testWidgets('ChangeNotifier', (WidgetTester tester) async {
final List<String> log = <String>[];
final VoidCallback listener = () { log.add('listener'); };
final VoidCallback listener1 = () { log.add('listener1'); };
final VoidCallback listener2 = () { log.add('listener2'); };
final VoidCallback badListener = () {
log.add('badListener');
throw null;
};
final TestNotifier test = TestNotifier();
test.addListener(listener);
test.addListener(listener);
test.notify();
expect(log, <String>['listener', 'listener']);
log.clear();
test.removeListener(listener);
test.notify();
expect(log, <String>['listener']);
log.clear();
test.removeListener(listener);
test.notify();
expect(log, <String>[]);
log.clear();
test.removeListener(listener);
test.notify();
expect(log, <String>[]);
log.clear();
test.addListener(listener);
test.notify();
expect(log, <String>['listener']);
log.clear();
test.addListener(listener1);
test.notify();
expect(log, <String>['listener', 'listener1']);
log.clear();
test.addListener(listener2);
test.notify();
expect(log, <String>['listener', 'listener1', 'listener2']);
log.clear();
test.removeListener(listener1);
test.notify();
expect(log, <String>['listener', 'listener2']);
log.clear();
test.addListener(listener1);
test.notify();
expect(log, <String>['listener', 'listener2', 'listener1']);
log.clear();
test.addListener(badListener);
test.notify();
expect(log, <String>['listener', 'listener2', 'listener1', 'badListener']);
expect(tester.takeException(), isNullThrownError);
log.clear();
test.addListener(listener1);
test.removeListener(listener);
test.removeListener(listener1);
test.removeListener(listener2);
test.addListener(listener2);
test.notify();
expect(log, <String>['badListener', 'listener1', 'listener2']);
expect(tester.takeException(), isNullThrownError);
log.clear();
});
test('ChangeNotifier with mutating listener', () {
final TestNotifier test = TestNotifier();
final List<String> log = <String>[];
final VoidCallback listener1 = () { log.add('listener1'); };
final VoidCallback listener3 = () { log.add('listener3'); };
final VoidCallback listener4 = () { log.add('listener4'); };
final VoidCallback listener2 = () {
log.add('listener2');
test.removeListener(listener1);
test.removeListener(listener3);
test.addListener(listener4);
};
test.addListener(listener1);
test.addListener(listener2);
test.addListener(listener3);
test.notify();
expect(log, <String>['listener1', 'listener2']);
log.clear();
test.notify();
expect(log, <String>['listener2', 'listener4']);
log.clear();
test.notify();
expect(log, <String>['listener2', 'listener4', 'listener4']);
log.clear();
});
test('During notifyListeners, a listener was added and removed immediately', () {
final TestNotifier source = TestNotifier();
final List<String> log = <String>[];
final VoidCallback listener3 = () { log.add('listener3'); };
final VoidCallback listener2 = () { log.add('listener2'); };
void listener1() {
log.add('listener1');
source.addListener(listener2);
source.removeListener(listener2);
source.addListener(listener3);
}
source.addListener(listener1);
source.notify();
expect(log, <String>['listener1']);
});
test(
'If a listener in the middle of the list of listeners removes itself, '
'notifyListeners still notifies all listeners', () {
final TestNotifier source = TestNotifier();
final List<String> log = <String>[];
void selfRemovingListener() {
log.add('selfRemovingListener');
source.removeListener(selfRemovingListener);
}
final VoidCallback listener1 = () { log.add('listener1'); };
source.addListener(listener1);
source.addListener(selfRemovingListener);
source.addListener(listener1);
source.notify();
expect(log, <String>['listener1', 'selfRemovingListener', 'listener1']);
});
test('If the first listener removes itself, notifyListeners still notify all listeners', () {
final TestNotifier source = TestNotifier();
final List<String> log = <String>[];
void selfRemovingListener() {
log.add('selfRemovingListener');
source.removeListener(selfRemovingListener);
}
void listener1() {
log.add('listener1');
}
source.addListener(selfRemovingListener);
source.addListener(listener1);
source.notifyListeners();
expect(log, <String>['selfRemovingListener', 'listener1']);
});
test('Merging change notifiers', () {
final TestNotifier source1 = TestNotifier();
final TestNotifier source2 = TestNotifier();
final TestNotifier source3 = TestNotifier();
final List<String> log = <String>[];
final Listenable merged = Listenable.merge(<Listenable>[source1, source2]);
final VoidCallback listener1 = () { log.add('listener1'); };
final VoidCallback listener2 = () { log.add('listener2'); };
merged.addListener(listener1);
source1.notify();
source2.notify();
source3.notify();
expect(log, <String>['listener1', 'listener1']);
log.clear();
merged.removeListener(listener1);
source1.notify();
source2.notify();
source3.notify();
expect(log, isEmpty);
log.clear();
merged.addListener(listener1);
merged.addListener(listener2);
source1.notify();
source2.notify();
source3.notify();
expect(log, <String>['listener1', 'listener2', 'listener1', 'listener2']);
log.clear();
});
test('Merging change notifiers ignores null', () {
final TestNotifier source1 = TestNotifier();
final TestNotifier source2 = TestNotifier();
final List<String> log = <String>[];
final Listenable merged = Listenable.merge(<Listenable>[null, source1, null, source2, null]);
final VoidCallback listener = () { log.add('listener'); };
merged.addListener(listener);
source1.notify();
source2.notify();
expect(log, <String>['listener', 'listener']);
log.clear();
});
test('Can remove from merged notifier', () {
final TestNotifier source1 = TestNotifier();
final TestNotifier source2 = TestNotifier();
final List<String> log = <String>[];
final Listenable merged = Listenable.merge(<Listenable>[source1, source2]);
final VoidCallback listener = () { log.add('listener'); };
merged.addListener(listener);
source1.notify();
source2.notify();
expect(log, <String>['listener', 'listener']);
log.clear();
merged.removeListener(listener);
source1.notify();
source2.notify();
expect(log, isEmpty);
});
test('Cannot use a disposed ChangeNotifier', () {
final TestNotifier source = TestNotifier();
source.dispose();
expect(() { source.addListener(() { }); }, throwsFlutterError);
expect(() { source.removeListener(() { }); }, throwsFlutterError);
expect(() { source.dispose(); }, throwsFlutterError);
expect(() { source.notify(); }, throwsFlutterError);
});
test('Value notifier', () {
final ValueNotifier<double> notifier = ValueNotifier<double>(2.0);
final List<double> log = <double>[];
final VoidCallback listener = () { log.add(notifier.value); };
notifier.addListener(listener);
notifier.value = 3.0;
expect(log, equals(<double>[ 3.0 ]));
log.clear();
notifier.value = 3.0;
expect(log, isEmpty);
});
test('Listenable.merge toString', () {
final TestNotifier source1 = TestNotifier();
final TestNotifier source2 = TestNotifier();
Listenable listenableUnderTest = Listenable.merge(<Listenable>[]);
expect(listenableUnderTest.toString(), 'Listenable.merge([])');
listenableUnderTest = Listenable.merge(<Listenable>[null]);
expect(listenableUnderTest.toString(), 'Listenable.merge([null])');
listenableUnderTest = Listenable.merge(<Listenable>[source1]);
expect(
listenableUnderTest.toString(),
"Listenable.merge([Instance of 'TestNotifier'])",
);
listenableUnderTest = Listenable.merge(<Listenable>[source1, source2]);
expect(
listenableUnderTest.toString(),
"Listenable.merge([Instance of 'TestNotifier', Instance of 'TestNotifier'])",
);
listenableUnderTest = Listenable.merge(<Listenable>[null, source2]);
expect(
listenableUnderTest.toString(),
"Listenable.merge([null, Instance of 'TestNotifier'])",
);
});
test('Listenable.merge does not leak', () {
// Regression test for https://github.com/flutter/flutter/issues/25163.
final TestNotifier source1 = TestNotifier();
final TestNotifier source2 = TestNotifier();
final VoidCallback fakeListener = () { };
final Listenable listenableUnderTest = Listenable.merge(<Listenable>[source1, source2]);
expect(source1.isListenedTo, isFalse);
expect(source2.isListenedTo, isFalse);
listenableUnderTest.addListener(fakeListener);
expect(source1.isListenedTo, isTrue);
expect(source2.isListenedTo, isTrue);
listenableUnderTest.removeListener(fakeListener);
expect(source1.isListenedTo, isFalse);
expect(source2.isListenedTo, isFalse);
});
test('hasListeners', () {
final HasListenersTester<bool> notifier = HasListenersTester<bool>(true);
expect(notifier.testHasListeners, isFalse);
void test1() { }
void test2() { }
notifier.addListener(test1);
expect(notifier.testHasListeners, isTrue);
notifier.addListener(test1);
expect(notifier.testHasListeners, isTrue);
notifier.removeListener(test1);
expect(notifier.testHasListeners, isTrue);
notifier.removeListener(test1);
expect(notifier.testHasListeners, isFalse);
notifier.addListener(test1);
expect(notifier.testHasListeners, isTrue);
notifier.addListener(test2);
expect(notifier.testHasListeners, isTrue);
notifier.removeListener(test1);
expect(notifier.testHasListeners, isTrue);
notifier.removeListener(test2);
expect(notifier.testHasListeners, isFalse);
});
test('ChangeNotifier as a mixin', () {
// We document that this is a valid way to use this class.
final B b = B();
int notifications = 0;
b.addListener(() {
notifications += 1;
});
expect(b.result, isFalse);
expect(notifications, 0);
b.test();
expect(b.result, isTrue);
expect(notifications, 1);
});
test('Throws FlutterError when disposed and called', () {
final TestNotifier testNotifier = TestNotifier();
testNotifier.dispose();
FlutterError error;
try {
testNotifier.dispose();
} on FlutterError catch (e) {
error = e;
}
expect(error, isNotNull);
expect(error, isFlutterError);
expect(error.toStringDeep(), equalsIgnoringHashCodes(
'FlutterError\n'
' A TestNotifier was used after being disposed.\n'
' Once you have called dispose() on a TestNotifier, it can no\n'
' longer be used.\n'
));
});
}