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Add another test to ImageStream (#26693)

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xster 2019-01-22 11:29:00 -08:00 committed by GitHub
parent 8098b5e63e
commit 890085e9b0
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52
packages/flutter/test/widgets/image_test.dart
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@ -581,6 +581,58 @@ void main() {
expect(capturedImage, isNull); // The image stream listeners should never be called.
});
testWidgets('Removing listener FIFO removes exactly one listener and error listener', (WidgetTester tester) async {
// To make sure that a single listener removal doesn't only happen
// accidentally as described in https://github.com/flutter/flutter/pull/25865#discussion_r244851565.
int errorListener1Called = 0;
int errorListener2Called = 0;
int errorListener3Called = 0;
ImageInfo capturedImage;
final ImageErrorListener errorListener1 = (dynamic exception, StackTrace stackTrace) {
errorListener1Called++;
};
final ImageErrorListener errorListener2 = (dynamic exception, StackTrace stackTrace) {
errorListener2Called++;
};
final ImageErrorListener errorListener3 = (dynamic exception, StackTrace stackTrace) {
errorListener3Called++;
};
final ImageListener listener = (ImageInfo info, bool synchronous) {
capturedImage = info;
};
final Exception testException = Exception('cannot resolve host');
final StackTrace testStack = StackTrace.current;
final TestImageProvider imageProvider = TestImageProvider();
imageProvider._streamCompleter.addListener(listener, onError: errorListener1);
imageProvider._streamCompleter.addListener(listener, onError: errorListener2);
imageProvider._streamCompleter.addListener(listener, onError: errorListener3);
// Remove listener. It should remove exactly the first one and the associated
// errorListener1.
imageProvider._streamCompleter.removeListener(listener);
ImageConfiguration configuration;
await tester.pumpWidget(
Builder(
builder: (BuildContext context) {
configuration = createLocalImageConfiguration(context);
return Container();
},
),
);
imageProvider.resolve(configuration);
imageProvider.fail(testException, testStack);
expect(tester.binding.microtaskCount, 1);
await tester.idle(); // Let the failed completer's future hit the stream completer.
expect(tester.binding.microtaskCount, 0);
expect(errorListener1Called, 0);
expect(errorListener2Called, 1);
expect(errorListener3Called, 1);
expect(capturedImage, isNull); // The image stream listeners should never be called.
});
testWidgets('Image.memory control test', (WidgetTester tester) async {
await tester.pumpWidget(Image.memory(Uint8List.fromList(kTransparentImage), excludeFromSemantics: true,));
});