// 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. import 'dart:ui' as ui; import 'package:flutter_test/flutter_test.dart'; Future<ui.Image> createTestImage(int width, int height, ui.Color color) { final ui.Paint paint = ui.Paint() ..style = ui.PaintingStyle.stroke ..strokeWidth = 1.0 ..color = color; final ui.PictureRecorder recorder = ui.PictureRecorder(); final ui.Canvas pictureCanvas = ui.Canvas(recorder); pictureCanvas.drawCircle(Offset.zero, 20.0, paint); final ui.Picture picture = recorder.endRecording(); return picture.toImage(width, height); } void main() { const ui.Color red = ui.Color.fromARGB(255, 255, 0, 0); const ui.Color green = ui.Color.fromARGB(255, 0, 255, 0); const ui.Color transparentRed = ui.Color.fromARGB(128, 255, 0, 0); group('succeeds', () { testWidgets('when images have the same content', (WidgetTester tester) async { await expectLater( await createTestImage(100, 100, red), matchesReferenceImage(await createTestImage(100, 100, red)), ); await expectLater( await createTestImage(100, 100, green), matchesReferenceImage(await createTestImage(100, 100, green)), ); await expectLater( await createTestImage(100, 100, transparentRed), matchesReferenceImage(await createTestImage(100, 100, transparentRed)), ); }); testWidgets('when images are identical', (WidgetTester tester) async { final ui.Image image = await createTestImage(100, 100, red); await expectLater(image, matchesReferenceImage(image)); }); }); group('fails', () { testWidgets('when image sizes do not match', (WidgetTester tester) async { final ui.Image red50 = await createTestImage(50, 50, red); final ui.Image red100 = await createTestImage(100, 100, red); expect( await matchesReferenceImage(red50).matchAsync(red100), equals('does not match as width or height do not match. [100×100] != [50×50]'), ); }); testWidgets('when image pixels do not match', (WidgetTester tester) async { final ui.Image red100 = await createTestImage(100, 100, red); final ui.Image transparentRed100 = await createTestImage(100, 100, transparentRed); expect( await matchesReferenceImage(red100).matchAsync(transparentRed100), equals('does not match on 57 pixels'), ); final ui.Image green100 = await createTestImage(100, 100, green); expect( await matchesReferenceImage(red100).matchAsync(green100), equals('does not match on 57 pixels'), ); }); }); }