[Impeller] Skia gold for flutter_tester dart tests.

.ci.yaml

@@ -293,6 +293,10 @@ targets:
       add_recipes_cq: "true"
       release_build: "true"
       config_name: linux_host_engine
+      dependencies: >-
+        [
+          {"dependency": "goldctl", "version": "git_revision:f808dcff91b221ae313e540c09d79696cd08b8de"}
+        ]
     drone_dimensions:
       - os=Linux
 

ci/builders/linux_host_engine.json

@@ -185,6 +185,12 @@
                 "device_type=none",
                 "os=Linux"
             ],
+            "dependencies": [
+                {
+                    "dependency": "goldctl",
+                    "version": "git_revision:dddc0623e63150cbbafdcb273d4048f329e1dd09"
+                }
+            ],
             "gclient_variables": {
                 "download_android_deps": false
             },

impeller/golden_tests_harvester/bin/golden_tests_harvester.dart

@@ -16,13 +16,16 @@ bool get isLuciEnv => Platform.environment.containsKey(_kLuciEnvName);
 
 /// Fake SkiaGoldClient that is used if the harvester is run outside of Luci.
 class FakeSkiaGoldClient implements SkiaGoldClient {
-  FakeSkiaGoldClient(this._workingDirectory, {this.dimensions});
+  FakeSkiaGoldClient(this._workingDirectory, {this.dimensions, this.verbose = false});
 
   final Directory _workingDirectory;
 
   @override
   final Map<String, String>? dimensions;
 
+  @override
+  final bool verbose;
+
   @override
   Future<void> addImg(String testName, File goldenFile,
       {double differentPixelsRate = 0.01,

testing/dart/BUILD.gn

@@ -48,9 +48,11 @@ tests = [
 ]
 
 foreach(test, tests) {
+  skia_gold_work_dir = rebase_path("$root_gen_dir/skia_gold_$test")
   flutter_frontend_server("compile_$test") {
     main_dart = test
     kernel_output = "$root_gen_dir/$test.dill"
+    extra_args = [ "-DkSkiaGoldWorkDirectory=$skia_gold_work_dir" ]
     package_config = ".dart_tool/package_config.json"
   }
 }

testing/dart/canvas_test.dart

@@ -12,6 +12,7 @@ import 'package:litetest/litetest.dart';
 import 'package:path/path.dart' as path;
 import 'package:vector_math/vector_math_64.dart';
 
+import 'goldens.dart';
 import 'impeller_enabled.dart';
 
 typedef CanvasCallback = void Function(Canvas canvas);
@@ -123,59 +124,9 @@ void testNoCrashes() {
   });
 }
 
-/// @returns true When the images are reasonably similar.
-/// @todo Make the search actually fuzzy to a certain degree.
-Future<bool> fuzzyCompareImages(Image golden, Image img) async {
-  if (golden.width != img.width || golden.height != img.height) {
-    return false;
-  }
-  int getPixel(ByteData data, int x, int y) => data.getUint32((x + y * golden.width) * 4);
-  final ByteData goldenData = (await golden.toByteData())!;
-  final ByteData imgData = (await img.toByteData())!;
-  for (int y = 0; y < golden.height; y++) {
-    for (int x = 0; x < golden.width; x++) {
-      if (getPixel(goldenData, x, y) != getPixel(imgData, x, y)) {
-        return false;
-      }
-    }
-  }
-  return true;
-}
-
-Future<void> saveTestImage(Image image, String filename) async {
-  final String imagesPath = path.join('flutter', 'testing', 'resources');
-  final ByteData pngData = (await image.toByteData(format: ImageByteFormat.png))!;
-  final String outPath = path.join(imagesPath, filename);
-  File(outPath).writeAsBytesSync(pngData.buffer.asUint8List());
-  print('wrote: $outPath');
-}
-
-/// @returns true When the images are reasonably similar.
-Future<bool> fuzzyGoldenImageCompare(
-    Image image, String goldenImageName) async {
-  final String imagesPath = path.join('flutter', 'testing', 'resources');
-  final File file = File(path.join(imagesPath, goldenImageName));
-
-  bool areEqual = false;
-
-  if (file.existsSync()) {
-    final Uint8List goldenData = await file.readAsBytes();
-
-    final Codec codec = await instantiateImageCodec(goldenData);
-    final FrameInfo frame = await codec.getNextFrame();
-    expect(frame.image.height, equals(image.height));
-    expect(frame.image.width, equals(image.width));
-
-    areEqual = await fuzzyCompareImages(frame.image, image);
-  }
+void main() async {
+  final ImageComparer comparer = await ImageComparer.create();
 
-  if (!areEqual) {
-    saveTestImage(image, 'found_$goldenImageName');
-  }
-  return areEqual;
-}
-
-void main() {
   testNoCrashes();
 
   test('Simple .toImage', () async {
@@ -190,11 +141,8 @@ void main() {
     }, 100, 100);
     expect(image.width, equals(100));
     expect(image.height, equals(100));
-
-    final bool areEqual =
-        await fuzzyGoldenImageCompare(image, 'canvas_test_toImage.png');
-    expect(areEqual, true);
-  }, skip: impellerEnabled);
+    await comparer.addGoldenImage(image, 'canvas_test_toImage.png');
+  });
 
   Gradient makeGradient() {
     return Gradient.linear(
@@ -212,10 +160,8 @@ void main() {
     expect(image.width, equals(100));
     expect(image.height, equals(100));
 
-    final bool areEqual =
-        await fuzzyGoldenImageCompare(image, 'canvas_test_dithered_gradient.png');
-    expect(areEqual, true);
-  }, skip: !Platform.isLinux || impellerEnabled); // https://github.com/flutter/flutter/issues/53784
+    await comparer.addGoldenImage(image, 'canvas_test_dithered_gradient.png');
+  });
 
   test('Null values allowed for drawAtlas methods', () async {
     final Image image = await createImage(100, 100);
@@ -302,12 +248,8 @@ void main() {
       });
     }, width, height);
 
-    final bool areEqual = await fuzzyCompareImages(incrementalMatrixImage, combinedMatrixImage);
+    final bool areEqual = await comparer.fuzzyCompareImages(incrementalMatrixImage, combinedMatrixImage);
 
-    if (!areEqual) {
-      saveTestImage(incrementalMatrixImage, 'incremental_3D_transform_test_image.png');
-      saveTestImage(combinedMatrixImage, 'combined_3D_transform_test_image.png');
-    }
     expect(areEqual, true);
   });
 
@@ -348,10 +290,8 @@ void main() {
     expect(image.width, equals(200));
     expect(image.height, equals(250));
 
-    final bool areEqual =
-        await fuzzyGoldenImageCompare(image, 'dotted_path_effect_mixed_with_stroked_geometry.png');
-    expect(areEqual, true);
-  }, skip: !Platform.isLinux || impellerEnabled); // https://github.com/flutter/flutter/issues/53784
+    await comparer.addGoldenImage(image, 'dotted_path_effect_mixed_with_stroked_geometry.png');
+  });
 
   test('Gradients with matrices in Paragraphs render correctly', () async {
     final Image image = await toImage((Canvas canvas) {
@@ -400,10 +340,8 @@ void main() {
     expect(image.width, equals(600));
     expect(image.height, equals(400));
 
-    final bool areEqual =
-    await fuzzyGoldenImageCompare(image, 'text_with_gradient_with_matrix.png');
-    expect(areEqual, true);
-  }, skip: !Platform.isLinux || impellerEnabled); // https://github.com/flutter/flutter/issues/53784
+    await comparer.addGoldenImage(image, 'text_with_gradient_with_matrix.png');
+  });
 
   test('toImageSync - too big', () async {
     PictureRecorder recorder = PictureRecorder();
@@ -602,8 +540,8 @@ void main() {
     final Image tofuImage = await drawText('>\b<');
 
     // The tab's image should be identical to the space's image but not the tofu's image.
-    final bool tabToSpaceComparison = await fuzzyCompareImages(tabImage, spaceImage);
-    final bool tabToTofuComparison = await fuzzyCompareImages(tabImage, tofuImage);
+    final bool tabToSpaceComparison = await comparer.fuzzyCompareImages(tabImage, spaceImage);
+    final bool tabToTofuComparison = await comparer.fuzzyCompareImages(tabImage, tofuImage);
 
     expect(tabToSpaceComparison, isTrue);
     expect(tabToTofuComparison, isFalse);

testing/dart/goldens.dart

@@ -0,0 +1,129 @@
+// Copyright 2013 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:io';
+import 'dart:typed_data';
+import 'dart:ui';
+
+import 'package:path/path.dart' as path;
+import 'package:skia_gold_client/skia_gold_client.dart';
+
+import 'impeller_enabled.dart';
+
+const String _kSkiaGoldWorkDirectoryKey = 'kSkiaGoldWorkDirectory';
+
+/// A helper for doing image comparison (golden) tests.
+///
+/// Contains utilities for comparing two images in memory that are expected to
+/// be identical, or for adding images to Skia gold for comparison.
+class ImageComparer {
+  ImageComparer._({
+    required SkiaGoldClient client,
+  }) : _client = client;
+
+  // Avoid talking to Skia gold for the force-multithreading variants.
+  static bool get _useSkiaGold =>
+      !Platform.executableArguments.contains('--force-multithreading');
+
+  /// Creates an image comparer and authorizes.
+  static Future<ImageComparer> create({
+    bool verbose = false,
+  }) async {
+    const String workDirectoryPath =
+        String.fromEnvironment(_kSkiaGoldWorkDirectoryKey);
+    if (workDirectoryPath.isEmpty) {
+      throw UnsupportedError(
+          'Using ImageComparer requries defining kSkiaGoldWorkDirectoryKey.');
+    }
+
+    final Directory workDirectory = Directory(
+      impellerEnabled ? '${workDirectoryPath}_iplr' : workDirectoryPath,
+    )..createSync();
+    final Map<String, String> dimensions = <String, String>{
+      'impeller_enabled': impellerEnabled.toString(),
+    };
+    final SkiaGoldClient client = isSkiaGoldClientAvailable && _useSkiaGold
+        ? SkiaGoldClient(workDirectory,
+            dimensions: dimensions, verbose: verbose)
+        : _FakeSkiaGoldClient(workDirectory, dimensions, verbose: verbose);
+
+    await client.auth();
+    return ImageComparer._(client: client);
+  }
+
+  final SkiaGoldClient _client;
+
+  /// Adds an [Image] to Skia Gold for comparison.
+  ///
+  /// The [fileName] must be unique.
+  Future<void> addGoldenImage(Image image, String fileName) async {
+    final ByteData data =
+        (await image.toByteData(format: ImageByteFormat.png))!;
+
+    final File file = File(path.join(_client.workDirectory.path, fileName))
+      ..writeAsBytesSync(data.buffer.asUint8List());
+    await _client.addImg(
+      fileName,
+      file,
+      screenshotSize: image.width * image.height,
+    ).catchError((dynamic error) {
+      print('Skia gold comparison failed: $error');
+      throw Exception('Failed comparison: $fileName');
+    });
+  }
+
+  Future<bool> fuzzyCompareImages(Image golden, Image testImage) async {
+    if (golden.width != testImage.width || golden.height != testImage.height) {
+      return false;
+    }
+    int getPixel(ByteData data, int x, int y) =>
+        data.getUint32((x + y * golden.width) * 4);
+    final ByteData goldenData = (await golden.toByteData())!;
+    final ByteData testImageData = (await testImage.toByteData())!;
+    for (int y = 0; y < golden.height; y++) {
+      for (int x = 0; x < golden.width; x++) {
+        if (getPixel(goldenData, x, y) != getPixel(testImageData, x, y)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+}
+
+// TODO(dnfield): add local comparison against baseline,
+// https://github.com/flutter/flutter/issues/136831
+class _FakeSkiaGoldClient implements SkiaGoldClient {
+  _FakeSkiaGoldClient(
+    this.workDirectory,
+    this.dimensions, {
+    this.verbose = false,
+  });
+
+  @override
+  final Directory workDirectory;
+
+  @override
+  final Map<String, String> dimensions;
+
+  @override
+  final bool verbose;
+
+  @override
+  Future<void> auth() async {}
+
+  @override
+  Future<void> addImg(
+    String testName,
+    File goldenFile, {
+    double differentPixelsRate = 0.01,
+    int pixelColorDelta = 0,
+    required int screenshotSize,
+  }) async {}
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) {
+    throw UnimplementedError(invocation.memberName.toString().split('"')[1]);
+  }
+}

testing/dart/pubspec.yaml

@@ -19,6 +19,7 @@ environment:
 dependencies:
   litetest: any
   path: any
+  skia_gold_client: any
   sky_engine: any
   vector_math: any
   vm_service: any
@@ -29,8 +30,12 @@ dependency_overrides:
     path: ../../../third_party/dart/pkg/async_helper
   collection:
     path: ../../../third_party/dart/third_party/pkg/collection
+  crypto:
+    path: ../../../third_party/dart/third_party/pkg/crypto
   expect:
     path: ../../../third_party/dart/pkg/expect
+  file:
+    path: ../../../third_party/pkg/file/packages/file
   fixnum:
     path: ../../../third_party/dart/third_party/pkg/fixnum
   litetest:
@@ -39,12 +44,20 @@ dependency_overrides:
     path: ../../../third_party/dart/pkg/meta
   path:
     path: ../../../third_party/dart/third_party/pkg/path
+  platform:
+    path: ../../../third_party/pkg/platform
+  process:
+    path: ../../../third_party/pkg/process
   protobuf:
     path: ../../../third_party/dart/third_party/pkg/protobuf/protobuf
   smith:
     path: ../../../third_party/dart/pkg/smith
+  skia_gold_client:
+    path: ../skia_gold_client
   sky_engine:
     path: ../../sky/packages/sky_engine
+  typed_data:
+    path: ../../../third_party/dart/third_party/pkg/typed_data
   vector_math:
     path: ../../../third_party/pkg/vector_math
   vm_service: