[Impeller] Adds golden image tests. (flutter/engine#40366)

Added golden image tests to impeller

engine/src/flutter/.ci.yaml

@@ -380,6 +380,10 @@ targets:
     properties:
       release_build: "true"
       config_name: mac_host_engine
+      dependencies: >-
+        [
+          {"dependency": "goldctl", "version": "git_revision:3a77d0b12c697a840ca0c7705208e8622dc94603"}
+        ]
       $flutter/osx_sdk : >-
         { "sdk_version": "14a5294e" }
 

engine/src/flutter/BUILD.gn

@@ -181,9 +181,9 @@ group("unittests") {
     }
 
     if (is_mac) {
-      public_deps +=
-          [ "//flutter/shell/platform/darwin:flutter_channels_unittests" ]
       public_deps += [
+        "//flutter/impeller/golden_tests:impeller_golden_tests",
+        "//flutter/shell/platform/darwin:flutter_channels_unittests",
         "//flutter/third_party/spring_animation:spring_animation_unittests",
       ]
     }

engine/src/flutter/ci/builders/mac_host_engine.json

@@ -110,6 +110,9 @@
                 "os=Mac-12",
                 "cpu=x86"
             ],
+            "dependencies": [
+                {"dependency": "goldctl", "version": "git_revision:3a77d0b12c697a840ca0c7705208e8622dc94603"}
+            ],
             "gclient_custom_vars": {
                 "download_android_deps": false
             },
@@ -124,13 +127,27 @@
             "ninja": {
                 "config": "host_release",
                 "targets": [
-                    "flutter/shell/platform/darwin/macos:zip_macos_flutter_framework",
                     "flutter/build/archives:archive_gen_snapshot",
                     "flutter/build/archives:artifacts",
+                    "flutter/impeller/golden_tests:impeller_golden_tests",
+                    "flutter/shell/platform/darwin/macos:zip_macos_flutter_framework",
                     "flutter/tools/font-subset"
                 ]
             },
-            "tests": []
+            "tests": [
+                {
+                    "language": "python3",
+                    "name": "Impeller golden Tests for host_release",
+                    "parameters": [
+                        "--variant",
+                        "host_release",
+                        "--type",
+                        "impeller-golden"
+                    ],
+                    "script": "flutter/testing/run_tests.py",
+                    "type": "local"
+                }
+            ]
         },
         {
             "archives": [

engine/src/flutter/ci/licenses_golden/excluded_files

@@ -135,6 +135,14 @@
 ../../../flutter/impeller/geometry/README.md
 ../../../flutter/impeller/geometry/geometry_unittests.cc
 ../../../flutter/impeller/geometry/geometry_unittests.h
+../../../flutter/impeller/golden_tests/README.md
+../../../flutter/impeller/golden_tests_harvester/.dart_tool
+../../../flutter/impeller/golden_tests_harvester/.gitignore
+../../../flutter/impeller/golden_tests_harvester/README.md
+../../../flutter/impeller/golden_tests_harvester/analysis_options.yaml
+../../../flutter/impeller/golden_tests_harvester/pubspec.lock
+../../../flutter/impeller/golden_tests_harvester/pubspec.yaml
+../../../flutter/impeller/golden_tests_harvester/test
 ../../../flutter/impeller/image/README.md
 ../../../flutter/impeller/playground
 ../../../flutter/impeller/renderer/compute_subgroup_unittests.cc

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -1315,6 +1315,19 @@ ORIGIN: ../../../flutter/impeller/geometry/type_traits.cc + ../../../flutter/LIC
 ORIGIN: ../../../flutter/impeller/geometry/type_traits.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/vector.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/vector.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/golden_digest.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/golden_digest.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/golden_tests.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/main.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/metal_screenshot.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/metal_screenshot.mm + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/metal_screenshoter.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/metal_screenshoter.mm + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/working_directory.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests/working_directory.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests_harvester/bin/golden_tests_harvester.dart + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests_harvester/lib/golden_tests_harvester.dart + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/golden_tests_harvester/lib/logger.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/image/backends/skia/compressed_image_skia.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/image/backends/skia/compressed_image_skia.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/image/compressed_image.cc + ../../../flutter/LICENSE
@@ -3856,6 +3869,19 @@ FILE: ../../../flutter/impeller/geometry/type_traits.cc
 FILE: ../../../flutter/impeller/geometry/type_traits.h
 FILE: ../../../flutter/impeller/geometry/vector.cc
 FILE: ../../../flutter/impeller/geometry/vector.h
+FILE: ../../../flutter/impeller/golden_tests/golden_digest.cc
+FILE: ../../../flutter/impeller/golden_tests/golden_digest.h
+FILE: ../../../flutter/impeller/golden_tests/golden_tests.cc
+FILE: ../../../flutter/impeller/golden_tests/main.cc
+FILE: ../../../flutter/impeller/golden_tests/metal_screenshot.h
+FILE: ../../../flutter/impeller/golden_tests/metal_screenshot.mm
+FILE: ../../../flutter/impeller/golden_tests/metal_screenshoter.h
+FILE: ../../../flutter/impeller/golden_tests/metal_screenshoter.mm
+FILE: ../../../flutter/impeller/golden_tests/working_directory.cc
+FILE: ../../../flutter/impeller/golden_tests/working_directory.h
+FILE: ../../../flutter/impeller/golden_tests_harvester/bin/golden_tests_harvester.dart
+FILE: ../../../flutter/impeller/golden_tests_harvester/lib/golden_tests_harvester.dart
+FILE: ../../../flutter/impeller/golden_tests_harvester/lib/logger.dart
 FILE: ../../../flutter/impeller/image/backends/skia/compressed_image_skia.cc
 FILE: ../../../flutter/impeller/image/backends/skia/compressed_image_skia.h
 FILE: ../../../flutter/impeller/image/compressed_image.cc

engine/src/flutter/impeller/golden_tests/BUILD.gn

@@ -0,0 +1,39 @@
+# 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("//flutter/common/config.gni")
+import("//flutter/impeller/tools/impeller.gni")
+
+if (is_mac) {
+  test_fixtures("impeller_golden_tests_fixtures") {
+    fixtures = []
+  }
+
+  impeller_component("impeller_golden_tests") {
+    target_type = "executable"
+
+    testonly = true
+
+    sources = [
+      "golden_digest.cc",
+      "golden_digest.h",
+      "golden_tests.cc",
+      "main.cc",
+      "metal_screenshot.h",
+      "metal_screenshot.mm",
+      "metal_screenshoter.h",
+      "metal_screenshoter.mm",
+      "working_directory.cc",
+      "working_directory.h",
+    ]
+
+    deps = [
+      ":impeller_golden_tests_fixtures",
+      "//flutter/impeller/aiks",
+      "//flutter/impeller/playground",
+      "//flutter/impeller/renderer/backend/metal:metal",
+      "//third_party/googletest:gtest",
+    ]
+  }
+}

engine/src/flutter/impeller/golden_tests/README.md

@@ -0,0 +1,20 @@
+# Impeller Golden Tests
+
+This is the executable that will generate the golden image results that can then
+be sent to Skia Gold vial the
+[golden_tests_harvester]("../golden_tests_harvester").
+
+Running these tests should happen from
+[//flutter/testing/run_tests.py](../../testing/run_tests.py). That will do all
+the steps to generate the golden images and transmit them to Skia Gold. If you
+run the tests locally it will not actually upload anything. That only happens if
+the script is executed from LUCI.
+
+Example invocation:
+
+```sh
+./run_tests.py --variant="host_debug_unopt_arm64" --type="impeller-golden"
+```
+
+Currently these tests are only supported on macOS and only test the Metal
+backend to Impeller.

engine/src/flutter/impeller/golden_tests/golden_digest.cc

@@ -0,0 +1,58 @@
+// 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.
+
+#include "impeller/golden_tests/golden_digest.h"
+
+#include <fstream>
+
+namespace impeller {
+namespace testing {
+
+GoldenDigest* GoldenDigest::instance_ = nullptr;
+
+GoldenDigest* GoldenDigest::Instance() {
+  if (!instance_) {
+    instance_ = new GoldenDigest();
+  }
+  return instance_;
+}
+
+GoldenDigest::GoldenDigest() {}
+
+void GoldenDigest::AddImage(const std::string& test_name,
+                            const std::string& filename,
+                            int32_t width,
+                            int32_t height) {
+  entries_.push_back({test_name, filename, width, height});
+}
+
+bool GoldenDigest::Write(WorkingDirectory* working_directory) {
+  std::ofstream fout;
+  fout.open(working_directory->GetFilenamePath("digest.json"));
+  if (!fout.good()) {
+    return false;
+  }
+
+  fout << "[" << std::endl;
+  bool is_first = true;
+  for (const auto& entry : entries_) {
+    if (!is_first) {
+      fout << "," << std::endl;
+      is_first = false;
+    }
+    fout << "  { "
+         << "\"testName\" : \"" << entry.test_name << "\", "
+         << "\"filename\" : \"" << entry.filename << "\", "
+         << "\"width\" : " << entry.width << ", "
+         << "\"height\" : " << entry.height << " "
+         << "}";
+  }
+  fout << std::endl << "]" << std::endl;
+
+  fout.close();
+  return true;
+}
+
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/golden_digest.h

@@ -0,0 +1,45 @@
+// 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.
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "flutter/fml/macros.h"
+#include "flutter/impeller/golden_tests/working_directory.h"
+
+namespace impeller {
+namespace testing {
+
+/// Manages a global variable for tracking instances of golden images.
+class GoldenDigest {
+ public:
+  static GoldenDigest* Instance();
+
+  void AddImage(const std::string& test_name,
+                const std::string& filename,
+                int32_t width,
+                int32_t height);
+
+  /// Writes a "digest.json" file to `working_directory`.
+  ///
+  /// Returns `true` on success.
+  bool Write(WorkingDirectory* working_directory);
+
+ private:
+  FML_DISALLOW_COPY_AND_ASSIGN(GoldenDigest);
+  GoldenDigest();
+  struct Entry {
+    std::string test_name;
+    std::string filename;
+    int32_t width;
+    int32_t height;
+  };
+
+  static GoldenDigest* instance_;
+  std::vector<Entry> entries_;
+};
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/golden_tests.cc

@@ -0,0 +1,79 @@
+// 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.
+
+#include "gtest/gtest.h"
+
+#include <sstream>
+
+#include "impeller/aiks/canvas.h"
+#include "impeller/entity/contents/conical_gradient_contents.h"
+#include "impeller/geometry/path_builder.h"
+#include "impeller/golden_tests/golden_digest.h"
+#include "impeller/golden_tests/metal_screenshot.h"
+#include "impeller/golden_tests/metal_screenshoter.h"
+#include "impeller/golden_tests/working_directory.h"
+
+namespace impeller {
+namespace testing {
+
+namespace {
+std::string GetTestName() {
+  std::string suite_name =
+      ::testing::UnitTest::GetInstance()->current_test_suite()->name();
+  std::string test_name =
+      ::testing::UnitTest::GetInstance()->current_test_info()->name();
+  std::stringstream ss;
+  ss << "impeller_" << suite_name << "_" << test_name;
+  return ss.str();
+}
+
+std::string GetGoldenFilename() {
+  return GetTestName() + ".png";
+}
+
+bool SaveScreenshot(std::unique_ptr<MetalScreenshot> screenshot) {
+  if (!screenshot || !screenshot->GetBytes()) {
+    return false;
+  }
+  std::string test_name = GetTestName();
+  std::string filename = GetGoldenFilename();
+  GoldenDigest::Instance()->AddImage(
+      test_name, filename, screenshot->GetWidth(), screenshot->GetHeight());
+  return screenshot->WriteToPNG(
+      WorkingDirectory::Instance()->GetFilenamePath(filename));
+}
+}  // namespace
+
+class GoldenTests : public ::testing::Test {
+ public:
+  GoldenTests() : screenshoter_(new MetalScreenshoter()) {}
+
+  MetalScreenshoter& Screenshoter() { return *screenshoter_; }
+
+ private:
+  std::unique_ptr<MetalScreenshoter> screenshoter_;
+};
+
+TEST_F(GoldenTests, ConicalGradient) {
+  Canvas canvas;
+  Paint paint;
+  paint.color_source_type = Paint::ColorSourceType::kConicalGradient;
+  paint.color_source = []() {
+    auto result = std::make_shared<ConicalGradientContents>();
+    result->SetCenterAndRadius(Point(125, 125), 125);
+    result->SetColors({Color(1.0, 0.0, 0.0, 1.0), Color(0.0, 0.0, 1.0, 1.0)});
+    result->SetStops({0, 1});
+    result->SetFocus(Point(180, 180), 0);
+    result->SetTileMode(Entity::TileMode::kClamp);
+    return result;
+  };
+  paint.stroke_width = 0.0;
+  paint.style = Paint::Style::kFill;
+  canvas.DrawRect(Rect(10, 10, 250, 250), paint);
+  Picture picture = canvas.EndRecordingAsPicture();
+  auto screenshot = Screenshoter().MakeScreenshot(std::move(picture));
+  ASSERT_TRUE(SaveScreenshot(std::move(screenshot)));
+}
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/main.cc

@@ -0,0 +1,61 @@
+// 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.
+
+#include <wordexp.h>
+
+#include "flutter/fml/backtrace.h"
+#include "flutter/fml/build_config.h"
+#include "flutter/fml/command_line.h"
+#include "flutter/fml/logging.h"
+#include "flutter/impeller/golden_tests/golden_digest.h"
+#include "flutter/impeller/golden_tests/working_directory.h"
+#include "gtest/gtest.h"
+
+namespace {
+void print_usage() {
+  std::cout << "usage: impeller_golden_tests --working_dir=<working_dir>"
+            << std::endl
+            << std::endl;
+  std::cout << "flags:" << std::endl;
+  std::cout << "  working_dir: Where the golden images will be generated and "
+               "uploaded to Skia Gold from."
+            << std::endl;
+}
+}  // namespace
+
+int main(int argc, char** argv) {
+  fml::InstallCrashHandler();
+  testing::InitGoogleTest(&argc, argv);
+  fml::CommandLine cmd = fml::CommandLineFromPlatformOrArgcArgv(argc, argv);
+
+  std::optional<std::string> working_dir;
+  for (const auto& option : cmd.options()) {
+    if (option.name == "working_dir") {
+      wordexp_t wordexp_result;
+      int code = wordexp(option.value.c_str(), &wordexp_result, 0);
+      FML_CHECK(code == 0);
+      FML_CHECK(wordexp_result.we_wordc != 0);
+      working_dir = wordexp_result.we_wordv[0];
+      wordfree(&wordexp_result);
+    }
+  }
+  if (!working_dir) {
+    std::cout << "required argument \"working_dir\" is missing." << std::endl
+              << std::endl;
+    print_usage();
+    return 1;
+  }
+
+  impeller::testing::WorkingDirectory::Instance()->SetPath(working_dir.value());
+  std::cout << "working directory: "
+            << impeller::testing::WorkingDirectory::Instance()->GetPath()
+            << std::endl;
+
+  int return_code = RUN_ALL_TESTS();
+  if (0 == return_code) {
+    impeller::testing::GoldenDigest::Instance()->Write(
+        impeller::testing::WorkingDirectory::Instance());
+  }
+  return return_code;
+}

engine/src/flutter/impeller/golden_tests/metal_screenshot.h

@@ -0,0 +1,39 @@
+// 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.
+
+#pragma once
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreImage/CoreImage.h>
+#include <string>
+
+#include "flutter/fml/macros.h"
+
+namespace impeller {
+namespace testing {
+
+class MetalScreenshoter;
+
+/// A screenshot that was produced from `MetalScreenshoter`.
+class MetalScreenshot {
+ public:
+  ~MetalScreenshot();
+
+  const UInt8* GetBytes() const;
+
+  size_t GetHeight() const;
+
+  size_t GetWidth() const;
+
+  bool WriteToPNG(const std::string& path) const;
+
+ private:
+  friend class MetalScreenshoter;
+  MetalScreenshot(CGImageRef cgImage);
+  FML_DISALLOW_COPY_AND_ASSIGN(MetalScreenshot);
+  CGImageRef cgImage_;
+  CFDataRef pixel_data_;
+};
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/metal_screenshot.mm

@@ -0,0 +1,52 @@
+// 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.
+
+#include "impeller/golden_tests/metal_screenshot.h"
+
+namespace impeller {
+namespace testing {
+
+MetalScreenshot::MetalScreenshot(CGImageRef cgImage) : cgImage_(cgImage) {
+  CGDataProviderRef data_provider = CGImageGetDataProvider(cgImage);
+  pixel_data_ = CGDataProviderCopyData(data_provider);
+}
+
+MetalScreenshot::~MetalScreenshot() {
+  CFRelease(pixel_data_);
+  CGImageRelease(cgImage_);
+}
+
+const UInt8* MetalScreenshot::GetBytes() const {
+  return CFDataGetBytePtr(pixel_data_);
+}
+
+size_t MetalScreenshot::GetHeight() const {
+  return CGImageGetHeight(cgImage_);
+}
+
+size_t MetalScreenshot::GetWidth() const {
+  return CGImageGetWidth(cgImage_);
+}
+
+bool MetalScreenshot::WriteToPNG(const std::string& path) const {
+  bool result = false;
+  NSURL* output_url =
+      [NSURL fileURLWithPath:[NSString stringWithUTF8String:path.c_str()]];
+  CGImageDestinationRef destination = CGImageDestinationCreateWithURL(
+      (__bridge CFURLRef)output_url, kUTTypePNG, 1, nullptr);
+  if (destination != nullptr) {
+    CGImageDestinationAddImage(destination, cgImage_,
+                               (__bridge CFDictionaryRef) @{});
+
+    if (CGImageDestinationFinalize(destination)) {
+      result = true;
+    }
+
+    CFRelease(destination);
+  }
+  return result;
+}
+
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/metal_screenshoter.h

@@ -0,0 +1,30 @@
+// 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.
+
+#pragma once
+
+#include "flutter/fml/macros.h"
+#include "flutter/impeller/aiks/picture.h"
+#include "flutter/impeller/golden_tests/metal_screenshot.h"
+#include "flutter/impeller/playground/playground_impl.h"
+
+namespace impeller {
+namespace testing {
+
+/// Converts `Picture`'s to `MetalScreenshot`'s with the playground backend.
+class MetalScreenshoter {
+ public:
+  MetalScreenshoter();
+
+  std::unique_ptr<MetalScreenshot> MakeScreenshot(Picture&& picture,
+                                                  const ISize& size = {300,
+                                                                       300});
+
+ private:
+  std::unique_ptr<PlaygroundImpl> playground_;
+  std::unique_ptr<AiksContext> aiks_context_;
+};
+
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/metal_screenshoter.mm

@@ -0,0 +1,55 @@
+// 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.
+
+#include "flutter/impeller/golden_tests/metal_screenshoter.h"
+
+#include <CoreImage/CoreImage.h>
+#include "impeller/renderer/backend/metal/context_mtl.h"
+#include "impeller/renderer/backend/metal/texture_mtl.h"
+#define GLFW_INCLUDE_NONE
+#include "third_party/glfw/include/GLFW/glfw3.h"
+
+namespace impeller {
+namespace testing {
+
+MetalScreenshoter::MetalScreenshoter() {
+  FML_CHECK(::glfwInit() == GLFW_TRUE);
+  playground_ = PlaygroundImpl::Create(PlaygroundBackend::kMetal);
+  aiks_context_.reset(new AiksContext(playground_->GetContext()));
+}
+
+std::unique_ptr<MetalScreenshot> MetalScreenshoter::MakeScreenshot(
+    Picture&& picture,
+    const ISize& size) {
+  std::shared_ptr<Image> image = picture.ToImage(*aiks_context_, size);
+  std::shared_ptr<Texture> texture = image->GetTexture();
+  id<MTLTexture> metal_texture =
+      std::static_pointer_cast<TextureMTL>(texture)->GetMTLTexture();
+
+  if (metal_texture.pixelFormat != MTLPixelFormatBGRA8Unorm) {
+    return {};
+  }
+
+  CIImage* ciImage = [[CIImage alloc] initWithMTLTexture:metal_texture
+                                                 options:@{}];
+  FML_CHECK(ciImage);
+
+  std::shared_ptr<Context> context = playground_->GetContext();
+  std::shared_ptr<ContextMTL> context_mtl =
+      std::static_pointer_cast<ContextMTL>(context);
+  CIContext* cicontext =
+      [CIContext contextWithMTLDevice:context_mtl->GetMTLDevice()];
+  FML_CHECK(context);
+
+  CIImage* flipped = [ciImage
+      imageByApplyingOrientation:kCGImagePropertyOrientationDownMirrored];
+
+  CGImageRef cgImage = [cicontext createCGImage:flipped
+                                       fromRect:[ciImage extent]];
+
+  return std::unique_ptr<MetalScreenshot>(new MetalScreenshot(cgImage));
+}
+
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/working_directory.cc

@@ -0,0 +1,35 @@
+// 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.
+
+#include "impeller/golden_tests/working_directory.h"
+
+#include "flutter/fml/paths.h"
+
+namespace impeller {
+namespace testing {
+
+WorkingDirectory* WorkingDirectory::instance_ = nullptr;
+
+WorkingDirectory::WorkingDirectory() {}
+
+WorkingDirectory* WorkingDirectory::Instance() {
+  if (!instance_) {
+    instance_ = new WorkingDirectory();
+  }
+  return instance_;
+}
+
+std::string WorkingDirectory::GetFilenamePath(
+    const std::string& filename) const {
+  return fml::paths::JoinPaths({path_, filename});
+}
+
+void WorkingDirectory::SetPath(const std::string& path) {
+  FML_CHECK(did_set_ == false);
+  path_ = path;
+  did_set_ = true;
+}
+
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests/working_directory.h

@@ -0,0 +1,35 @@
+// 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.
+
+#pragma once
+
+#include <string>
+
+#include "flutter/fml/macros.h"
+
+namespace impeller {
+namespace testing {
+
+/// Keeps track of the global variable for the specified working
+/// directory.
+class WorkingDirectory {
+ public:
+  static WorkingDirectory* Instance();
+
+  std::string GetFilenamePath(const std::string& filename) const;
+
+  void SetPath(const std::string& path);
+
+  const std::string& GetPath() const { return path_; }
+
+ private:
+  FML_DISALLOW_COPY_AND_ASSIGN(WorkingDirectory);
+  WorkingDirectory();
+  static WorkingDirectory* instance_;
+  std::string path_;
+  bool did_set_ = false;
+};
+
+}  // namespace testing
+}  // namespace impeller

engine/src/flutter/impeller/golden_tests_harvester/.gitignore

@@ -0,0 +1,3 @@
+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/

engine/src/flutter/impeller/golden_tests_harvester/README.md

@@ -0,0 +1,14 @@
+# Golden Tests Harvester
+
+Reaps the output of impeller's golden image tests and sends it to Skia gold.
+
+## Usage
+
+```sh
+cd $SRC
+./out/host_debug_unopt_arm64/impeller_golden_tests --working_dir=~/Desktop/temp
+cd flutter/impeller/golden_tests_harvester
+dart run ./bin/golden_tests_harvester.dart ~/Desktop/temp
+```
+
+See also [golden_tests](../golden_tests/).

engine/src/flutter/impeller/golden_tests_harvester/analysis_options.yaml

@@ -0,0 +1 @@
+include: ../../analysis_options.yaml

engine/src/flutter/impeller/golden_tests_harvester/bin/golden_tests_harvester.dart

@@ -0,0 +1,88 @@
+// 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 'package:golden_tests_harvester/golden_tests_harvester.dart';
+import 'package:process/src/interface/process_manager.dart';
+import 'package:skia_gold_client/skia_gold_client.dart';
+
+const String _kLuciEnvName = 'LUCI_CONTEXT';
+
+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);
+
+  final Directory _workingDirectory;
+
+  @override
+  Future<void> addImg(String testName, File goldenFile,
+      {double differentPixelsRate = 0.01,
+      int pixelColorDelta = 0,
+      required int screenshotSize}) async {
+    Logger.instance.log('addImg $testName ${goldenFile.path} $screenshotSize');
+  }
+
+  @override
+  Future<void> auth() async {
+    Logger.instance.log('auth');
+  }
+
+  @override
+  String cleanTestName(String fileName) {
+    throw UnimplementedError();
+  }
+
+  @override
+  Map<String, String>? get dimensions => throw UnimplementedError();
+
+  @override
+  List<String> getCIArguments() {
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<String?> getExpectationForTest(String testName) {
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<List<int>> getImageBytes(String imageHash) {
+    throw UnimplementedError();
+  }
+
+  @override
+  String getTraceID(String testName) {
+    throw UnimplementedError();
+  }
+
+  @override
+  HttpClient get httpClient => throw UnimplementedError();
+
+  @override
+  ProcessManager get process => throw UnimplementedError();
+
+  @override
+  Directory get workDirectory => _workingDirectory;
+}
+
+void _printUsage() {
+  Logger.instance
+      .log('dart run ./bin/golden_tests_harvester.dart <working_dir>');
+}
+
+Future<void> main(List<String> arguments) async {
+  if (arguments.length != 1) {
+    return _printUsage();
+  }
+
+  final Directory workDirectory = Directory(arguments[0]);
+  final SkiaGoldClient skiaGoldClient = isLuciEnv
+      ? SkiaGoldClient(workDirectory)
+      : FakeSkiaGoldClient(workDirectory);
+
+  await harvest(skiaGoldClient, workDirectory);
+}

engine/src/flutter/impeller/golden_tests_harvester/lib/golden_tests_harvester.dart

@@ -0,0 +1,46 @@
+// 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:convert';
+import 'dart:io';
+
+import 'package:path/path.dart' as p;
+import 'package:skia_gold_client/skia_gold_client.dart';
+
+import 'logger.dart';
+
+export 'logger.dart';
+
+/// Reads the digest inside of [workDirectory], sending tests to
+/// [skiaGoldClient].
+Future<void> harvest(
+    SkiaGoldClient skiaGoldClient, Directory workDirectory) async {
+  await skiaGoldClient.auth();
+
+  final File digest = File(p.join(workDirectory.path, 'digest.json'));
+  if (!digest.existsSync()) {
+    Logger.instance
+        .log('Error: digest.json does not exist in ${workDirectory.path}.');
+    return;
+  }
+  final Object? decoded = jsonDecode(digest.readAsStringSync());
+  final List<Object?> entries = (decoded as List<Object?>?)!;
+  final List<Future<void>> pendingComparisons = <Future<void>>[];
+  for (final Object? entry in entries) {
+    final Map<String, Object?> map = (entry as Map<String, Object?>?)!;
+    final String filename = (map['filename'] as String?)!;
+    final int width = (map['width'] as int?)!;
+    final int height = (map['height'] as int?)!;
+    final File goldenImage = File(p.join(workDirectory.path, filename));
+    final Future<void> future = skiaGoldClient
+        .addImg(filename, goldenImage, screenshotSize: width * height)
+        .catchError((dynamic err) {
+      Logger.instance.log('skia gold comparison failed: $err');
+      throw Exception('Failed comparison: $filename');
+    });
+    pendingComparisons.add(future);
+  }
+
+  await Future.wait(pendingComparisons);
+}

engine/src/flutter/impeller/golden_tests_harvester/lib/logger.dart

@@ -0,0 +1,20 @@
+// 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.
+
+/// Logs messages to the appropriate console.
+class Logger {
+  Logger._();
+
+  /// Singleton accessor for the [Logger].
+  static Logger get instance {
+    _instance ??= Logger._();
+    return _instance!;
+  }
+
+  static Logger? _instance;
+
+  /// Log [message] to the console.
+  // ignore: avoid_print
+  void log(String message) => print(message);
+}

engine/src/flutter/impeller/golden_tests_harvester/pubspec.yaml

@@ -0,0 +1,40 @@
+# 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.
+
+name: golden_tests_harvester
+publish_to: none
+environment:
+  sdk: '>=3.0.0-0 <4.0.0'
+
+# Do not add any dependencies that require more than what is provided in
+# //third_party/dart/pkg, //third_party/dart/third_party/pkg, or
+# //third_party/pkg. In particular, package:test is not usable here.
+
+# If you do add packages here, make sure you can run `pub get --offline`, and
+# check the .packages and .package_config to make sure all the paths are
+# relative to this directory into //third_party/dart, or //third_party/pkg
+dependencies:
+  crypto: any
+  path: any
+  process: any
+  skia_gold_client:
+    path: ../../testing/skia_gold_client
+
+dependency_overrides:
+  collection:
+    path: ../../../third_party/dart/third_party/pkg/collection
+  crypto:
+    path: ../../../third_party/dart/third_party/pkg/crypto
+  file:
+    path: ../../../third_party/pkg/file/packages/file
+  meta:
+    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
+  typed_data:
+    path: ../../../third_party/dart/third_party/pkg/typed_data

engine/src/flutter/impeller/golden_tests_harvester/test/golden_tests_harvester_test.dart

@@ -0,0 +1,5 @@
+// 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.
+
+void main() {}

engine/src/flutter/testing/run_tests.py

@@ -8,16 +8,19 @@
 A top level harness to run all unit-tests in a specific engine build.
 """
 
+from pathlib import Path
+
 import argparse
-import glob
+import csv
 import errno
+import glob
 import multiprocessing
 import os
 import re
 import subprocess
 import sys
+import tempfile
 import time
-import csv
 import xvfb
 
 SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
@@ -972,6 +975,46 @@ def run_engine_tasks_in_parallel(tasks):
     raise Exception()
 
 
+class DirectoryChange():
+  """
+  A scoped change in the CWD.
+  """
+  old_cwd: str = ''
+  new_cwd: str = ''
+
+  def __init__(self, new_cwd: str):
+    self.new_cwd = new_cwd
+
+  def __enter__(self):
+    self.old_cwd = os.getcwd()
+    os.chdir(self.new_cwd)
+
+  def __exit__(self, exception_type, exception_value, exception_traceback):
+    os.chdir(self.old_cwd)
+
+
+def run_impeller_golden_tests(build_dir: str):
+  """
+  Executes the impeller golden image tests from in the `variant` build.
+  """
+  tests_path: str = os.path.join(build_dir, 'impeller_golden_tests')
+  if not os.path.exists(tests_path):
+    raise Exception(
+        'Cannot find the "impeller_golden_tests" executable in "%s". You may need to build it.'
+        % (build_dir)
+    )
+  harvester_path: Path = Path(SCRIPT_DIR).parent.joinpath('impeller').joinpath(
+      'golden_tests_harvester'
+  )
+  with tempfile.TemporaryDirectory(prefix='impeller_golden') as temp_dir:
+    run_cmd([tests_path, '--working_dir=%s' % temp_dir])
+    with DirectoryChange(harvester_path):
+      run_cmd(['dart', 'pub', 'get'])
+      bin_path = Path('.').joinpath('bin'
+                                   ).joinpath('golden_tests_harvester.dart')
+      run_cmd(['dart', 'run', str(bin_path), temp_dir])
+
+
 def main():
   parser = argparse.ArgumentParser(
       description="""
@@ -980,7 +1023,14 @@ Flutter Wiki page on the subject: https://github.com/flutter/flutter/wiki/Testin
 """
   )
   all_types = [
-      'engine', 'dart', 'benchmarks', 'java', 'android', 'objc', 'font-subset'
+      'engine',
+      'dart',
+      'benchmarks',
+      'java',
+      'android',
+      'objc',
+      'font-subset',
+      'impeller-golden',
   ]
 
   parser.add_argument(
@@ -1171,6 +1221,9 @@ Flutter Wiki page on the subject: https://github.com/flutter/flutter/wiki/Testin
       'font-subset' in types) and args.variant not in variants_to_skip:
     run_cmd(['python3', 'test.py'], cwd=FONT_SUBSET_DIR)
 
+  if 'impeller-golden' in types:
+    run_impeller_golden_tests(build_dir)
+
 
 if __name__ == '__main__':
   sys.exit(main())

engine/src/flutter/tools/pub_get_offline.py

@@ -21,6 +21,7 @@ ENGINE_DIR = os.path.join(SRC_ROOT, 'flutter')
 
 ALL_PACKAGES = [
     os.path.join(ENGINE_DIR, "ci"),
+    os.path.join(ENGINE_DIR, "impeller", "golden_tests_harvester"),
     os.path.join(ENGINE_DIR, "flutter_frontend_server"),
     os.path.join(ENGINE_DIR, "shell", "vmservice"),
     os.path.join(ENGINE_DIR, "testing", "benchmark"),