Screenshot taken with LiveTestWidgetsFlutterBinding is truncated #66006
Description
Internal: b/168776765
When using LiveTestWidgetsFlutterBinding, screenshots of top level widgets are truncated.
Context: We're trying to support screenshot testing in g3 with package:integration_test, where the widgets binding inherits from LiveTestWidgetsFlutterBinding. The following is a minimal repro with just flutter test.
Steps to Reproduce
Run flutter test with the following test file:
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
void main() {
LiveTestWidgetsFlutterBinding();
testWidgets('goldens', (tester) async {
await tester.pumpWidget(buildTestApp());
await expectLater(
find.byType(MaterialApp), matchesGoldenFile('screenshot.png'));
});
}
Widget buildTestApp() {
final app = MaterialApp(
title: 'Test',
home: Scaffold(
appBar: AppBar(
title: Text('Title'),
),
),
);
// screenshot is taken for _LiveTestRenderView#c6f40
return app;
// screenshot is taken for RenderRepaintBoundary#f72ed
// return RepaintBoundary(child: app);
}Expected behavior: Screenshot covers the full MaterialApp.
Similar to this image from AutomatedTestWidgetsFlutterBinding (with L5 commented out)
Actual Image (which looks truncated)
When I added some instrumentation to the renderObject used for taking a screenshot at
The renderObject is a LiveTestRenderView: _LiveTestRenderView#c6f40.
Adding a RepaintBoundary around MaterialApp (the last second line of the snippet) fixes the issue.
LiveTestWidgetsFlutterBinding with RepaintBoundary Image
#12994 looks like it could be related. It is pretty unexpected that a RepaintBoundary is needed just for LiveTestWidgetsFlutterBinding, but not for the default AutomatedTestWidgetsFlutterBinding, so this could be a bug. With AutomatedTestWidgetsFlutterBinding, the renderObject used for the screenshot is RenderRepaintBoundary#1d14f.
Another thing I noticed is that if the following
is set to_paintMatrix = _getMatrix(size, 1.0, window)the correct bounds are used for the image, though this probably isn't the correct fix.
Doctor Output
[✓] Flutter (Channel master, 1.22.0-10.0.pre.39, on Mac OS X 10.15.3 19D76, locale en-US)
• Flutter version 1.22.0-10.0.pre.39 at /Users/jiahaog/dev/flutter
• Framework revision a8281e31af (2 weeks ago), 2020-09-01 10:57:59 -0700
• Engine revision 165abef0a2
• Dart version 2.10.0 (build 2.10.0-77.0.dev)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0-rc2)
• Android SDK at /Users/jiahaog/Library/Android/sdk
• Platform android-stable, build-tools 30.0.0-rc2
• Java binary at: /Applications/Android Studio with Blaze.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 11.3.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 11.3.1, Build version 11C505
• CocoaPods version 1.9.3
[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[!] Android Studio (version 4.1)
• Android Studio at /Applications/Android Studio with Blaze.app/Contents
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
[✓] Android Studio
• Android Studio at /Applications/Android Studio 3.5 Preview.app/Contents
• Flutter plugin version 33.4.2
• Dart plugin version 183.5901
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
[✓] VS Code (version 1.48.2)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.14.0
[✓] Connected device (3 available)
• iPhone 11 (mobile) • 5D77C64F-14CB-4C4B-B47D-62443C8678ED • ios • com.apple.CoreSimulator.SimRuntime.iOS-13-3 (simulator)
• Web Server (web) • web-server • web-javascript • Flutter Tools
• Chrome (web) • chrome • web-javascript • Google Chrome 85.0.4183.102
! Doctor found issues in 1 category.