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testWidgets screenshot
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/// Originally published on: https://gist.github.com/stevsct/fc84fee8bcc3271e2295d99d7c7ae49d | |
/// | |
/// Inspired by https://pub.dev/packages/spot | |
import 'dart:io'; | |
import 'dart:typed_data'; | |
import 'dart:ui' as ui; | |
import 'package:flutter/material.dart'; | |
import 'package:flutter/rendering.dart'; | |
import 'package:flutter_test/flutter_test.dart'; | |
extension TestScreenshotUtil on WidgetTester { | |
Future<void> takeScreenshot({required String name}) async { | |
final liveElement = binding.renderViewElement!; | |
late final Uint8List bytes; | |
await binding.runAsync(() async { | |
final image = await _captureImage(liveElement); | |
final byteData = await image.toByteData(format: ui.ImageByteFormat.png); | |
if (byteData == null) { | |
return 'Could not take screenshot'; | |
} | |
bytes = byteData.buffer.asUint8List(); | |
image.dispose(); | |
}); | |
final directory = Directory('./screenshots'); | |
if (!directory.existsSync()) { | |
directory.createSync(); | |
} | |
final file = File('./screenshots/$name.png'); | |
file.writeAsBytesSync(bytes); | |
} | |
Future<ui.Image> _captureImage(Element element) async { | |
assert(element.renderObject != null); | |
RenderObject renderObject = element.renderObject!; | |
while (!renderObject.isRepaintBoundary) { | |
// ignore: unnecessary_cast | |
renderObject = renderObject.parent! as RenderObject; | |
} | |
assert(!renderObject.debugNeedsPaint); | |
final OffsetLayer layer = renderObject.debugLayer! as OffsetLayer; | |
final ui.Image image = await layer.toImage(renderObject.paintBounds); | |
if (element.renderObject is RenderBox) { | |
final expectedSize = (element.renderObject as RenderBox?)!.size; | |
if (expectedSize.width != image.width || expectedSize.height != image.height) { | |
// ignore: avoid_print | |
print( | |
'Warning: The screenshot captured of ${element.toStringShort()} is ' | |
'larger (${image.width}, ${image.height}) than ' | |
'${element.toStringShort()} (${expectedSize.width}, ${expectedSize.height}) itself.\n' | |
'Wrap the ${element.toStringShort()} in a RepaintBoundary to be able to capture only that layer. ', | |
); | |
} | |
} | |
return image; | |
} | |
} |
Got it, thanks Steven!
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Hi
You could create an
utils
folder under yourtest
directory. Then in your widget test, you'll be able to call the method like this:The file will be located in
$PROJECT_DIR/screenshots