[web] enable CanvasKit tests using a local bundle fetched from CIPD (#92134)

.ci.yaml

@@ -1184,6 +1184,174 @@ targets:
       - bin/
       - .ci.yaml
 
+  - name: Linux web_canvaskit_tests_0
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "0"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
+  - name: Linux web_canvaskit_tests_1
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "1"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
+  - name: Linux web_canvaskit_tests_2
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "2"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
+  - name: Linux web_canvaskit_tests_3
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "3"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
+  - name: Linux web_canvaskit_tests_4
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "4"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
+  - name: Linux web_canvaskit_tests_5
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "5"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
+  - name: Linux web_canvaskit_tests_6
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "6"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
+  - name: Linux web_canvaskit_tests_7_last
+    bringup: true
+    recipe: flutter/flutter_drone
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "android_sdk"},
+          {"dependency": "chrome_and_driver"},
+          {"dependency": "goldctl"}
+        ]
+      shard: web_canvaskit_tests
+      subshard: "7_last"
+      tags: >
+        ["framework","hostonly","shard"]
+    scheduler: luci
+    runIf:
+      - dev/
+      - packages/
+      - bin/
+
   - name: Linux web_tool_tests
     recipe: flutter/flutter_drone
     timeout: 60

TESTOWNERS

@@ -225,6 +225,7 @@
 # web_integration_tests @yjbanov @flutter/web
 # web_long_running_tests @yjbanov @flutter/web
 # web_tests @yjbanov @flutter/web
+# web_canvaskit_tests @yjbanov @flutter/web
 # web_tool_tests @zanderso @flutter/tool
 # fuchsia_precache @zanderso @flutter/tool
 # skp_generator @Hixie

dev/bots/test.dart

@@ -74,13 +74,66 @@ const String kSubshardKey = 'SUBSHARD';
 int get webShardCount => Platform.environment.containsKey('WEB_SHARD_COUNT')
   ? int.parse(Platform.environment['WEB_SHARD_COUNT']!)
   : 8;
-/// Tests that we don't run on Web for compilation reasons.
+
+/// Tests that we don't run on Web.
+///
+/// In general avoid adding new tests here. If a test cannot run on the web
+/// because it fails at runtime, such as when a piece of functionality is not
+/// implemented or not implementable on the web, prefer using `skip` in the
+/// test code. Only add tests here that cannot be skipped using `skip`. For
+/// example:
+///
+///  * Test code cannot be compiled because it uses Dart VM-specific
+///    functionality. In this case `skip` doesn't help because the code cannot
+///    reach the point where it can even run the skipping logic.
+///  * Migrations. It is OK to put tests here that need to be temporarily
+///    disabled in certain modes because of some migration or initial bringup.
+///
+/// The key in the map is the renderer type that the list applies to. The value
+/// is the list of tests known to fail for that renderer.
 //
 // TODO(yjbanov): we're getting rid of this as part of https://github.com/flutter/flutter/projects/60
-const List<String> kWebTestFileKnownFailures = <String>[
+const Map<String, List<String>> kWebTestFileKnownFailures = <String, List<String>>{
+  'html': <String>[
+    // These tests are not compilable on the web due to dependencies on
+    // VM-specific functionality.
     'test/services/message_codecs_vm_test.dart',
     'test/examples/sector_layout_test.dart',
-];
+  ],
+  'canvaskit': <String>[
+    // These tests are not compilable on the web due to dependencies on
+    // VM-specific functionality.
+    'test/services/message_codecs_vm_test.dart',
+    'test/examples/sector_layout_test.dart',
+
+    // These tests are broken and need to be fixed.
+    // TODO(yjbanov): https://github.com/flutter/flutter/issues/71604
+    'test/painting/decoration_test.dart',
+    'test/material/text_selection_theme_test.dart',
+    'test/material/date_picker_test.dart',
+    'test/rendering/layers_test.dart',
+    'test/painting/text_style_test.dart',
+    'test/widgets/image_test.dart',
+    'test/cupertino/colors_test.dart',
+    'test/cupertino/slider_test.dart',
+    'test/material/text_field_test.dart',
+    'test/rendering/proxy_box_test.dart',
+    'test/widgets/app_overrides_test.dart',
+    'test/material/calendar_date_picker_test.dart',
+    'test/material/ink_paint_test.dart',
+    'test/rendering/editable_test.dart',
+    'test/cupertino/dialog_test.dart',
+    'test/widgets/shape_decoration_test.dart',
+    'test/material/time_picker_theme_test.dart',
+    'test/cupertino/picker_test.dart',
+    'test/material/chip_theme_test.dart',
+    'test/cupertino/nav_bar_test.dart',
+    'test/widgets/performance_overlay_test.dart',
+    'test/widgets/html_element_view_test.dart',
+    'test/cupertino/scaffold_test.dart',
+    'test/rendering/platform_view_test.dart',
+  ],
+};
 
 const String kSmokeTestShardName = 'smoke_tests';
 const List<String> _kAllBuildModes = <String>['debug', 'profile', 'release'];
@@ -143,8 +196,10 @@ Future<void> main(List<String> args) async {
       // web_tool_tests is also used by HHH: https://dart.googlesource.com/recipes/+/refs/heads/master/recipes/dart/flutter_engine.py
       'web_tool_tests': _runWebToolTests,
       'tool_integration_tests': _runIntegrationToolTests,
-      // All the unit/widget tests run using `flutter test --platform=chrome`
+      // All the unit/widget tests run using `flutter test --platform=chrome --web-renderer=html`
-      'web_tests': _runWebUnitTests,
+      'web_tests': _runWebHtmlUnitTests,
+      // All the unit/widget tests run using `flutter test --platform=chrome --web-renderer=canvaskit`
+      'web_canvaskit_tests': _runWebCanvasKitUnitTests,
       // All web integration tests
       'web_long_running_tests': _runWebLongRunningTests,
       'flutter_plugins': _runFlutterPluginsTests,
@@ -802,7 +857,15 @@ Future<void> _runFrameworkCoverage() async {
   }
 }
 
-Future<void> _runWebUnitTests() async {
+Future<void> _runWebHtmlUnitTests() {
+  return _runWebUnitTests('html');
+}
+
+Future<void> _runWebCanvasKitUnitTests() {
+  return _runWebUnitTests('canvaskit');
+}
+
+Future<void> _runWebUnitTests(String webRenderer) async {
   final Map<String, ShardRunner> subshards = <String, ShardRunner>{};
 
   final Directory flutterPackageDirectory = Directory(path.join(flutterRoot, 'packages', 'flutter'));
@@ -817,7 +880,7 @@ Future<void> _runWebUnitTests() async {
     )
     .whereType<File>()
     .map<String>((File file) => path.relative(file.path, from: flutterPackageDirectory.path))
-    .where((String filePath) => !kWebTestFileKnownFailures.contains(path.split(filePath).join('/')))
+    .where((String filePath) => !kWebTestFileKnownFailures[webRenderer]!.contains(path.split(filePath).join('/')))
     .toList()
     // Finally we shuffle the list because we want the average cost per file to be uniformly
     // distributed. If the list is not sorted then different shards and batches may have
@@ -832,6 +895,7 @@ Future<void> _runWebUnitTests() async {
   // This for loop computes all but the last shard.
   for (int index = 0; index < webShardCount - 1; index += 1) {
     subshards['$index'] = () => _runFlutterWebTest(
+      webRenderer,
       flutterPackageDirectory.path,
       allTests.sublist(
         index * testsPerShard,
@@ -846,6 +910,7 @@ Future<void> _runWebUnitTests() async {
   // between `.cirrus.yml` and `test.dart`.
   subshards['${webShardCount - 1}_last'] = () async {
     await _runFlutterWebTest(
+      webRenderer,
       flutterPackageDirectory.path,
       allTests.sublist(
         (webShardCount - 1) * testsPerShard,
@@ -853,10 +918,12 @@ Future<void> _runWebUnitTests() async {
       ),
     );
     await _runFlutterWebTest(
+      webRenderer,
       path.join(flutterRoot, 'packages', 'flutter_web_plugins'),
       <String>['test'],
     );
     await _runFlutterWebTest(
+      webRenderer,
       path.join(flutterRoot, 'packages', 'flutter_driver'),
       <String>[path.join('test', 'src', 'web_tests', 'web_extension_test.dart')],
     );
@@ -1421,7 +1488,7 @@ Future<void> _runWebDebugTest(String target, {
   }
 }
 
-Future<void> _runFlutterWebTest(String workingDirectory, List<String> tests) async {
+Future<void> _runFlutterWebTest(String webRenderer, String workingDirectory, List<String> tests) async {
   await runCommand(
     flutter,
     <String>[
@@ -1430,9 +1497,8 @@ Future<void> _runFlutterWebTest(String workingDirectory, List<String> tests) asy
         '--concurrency=1',  // do not parallelize on Cirrus, to reduce flakiness
       '-v',
       '--platform=chrome',
-      // TODO(ferhatb): Run web tests with both rendering backends.
+      '--web-renderer=$webRenderer',
-      '--web-renderer=html', // use html backend for web tests.
+      '--sound-null-safety',
-      '--sound-null-safety', // web tests do not autodetect yet.
       ...flutterTestArgs,
       ...tests,
     ],

packages/flutter_goldens_client/lib/skia_client.dart

@@ -19,6 +19,7 @@ import 'package:process/process.dart';
 const String _kFlutterRootKey = 'FLUTTER_ROOT';
 const String _kGoldctlKey = 'GOLDCTL';
 const String _kTestBrowserKey = 'FLUTTER_TEST_BROWSER';
+const String _kWebRendererKey = 'FLUTTER_WEB_RENDERER';
 
 /// A client for uploading image tests and making baseline requests to the
 /// Flutter Gold Dashboard.
@@ -368,6 +369,9 @@ class SkiaGoldClient {
     if (platform.environment[_kTestBrowserKey] != null) {
       keys['Browser'] = platform.environment[_kTestBrowserKey];
       keys['Platform'] = '${keys['Platform']}-browser';
+      if (platform.environment[_kWebRendererKey] == 'canvaskit') {
+        keys['WebRenderer'] = 'canvaskit';
+      }
     }
     return json.encode(keys);
   }
@@ -413,7 +417,10 @@ class SkiaGoldClient {
   /// the image keys.
   String getTraceID(String testName) {
     final Map<String, dynamic> keys = <String, dynamic>{
-      if (platform.environment[_kTestBrowserKey] != null) 'Browser' : platform.environment[_kTestBrowserKey],
+      if (platform.environment[_kTestBrowserKey] != null)
+        'Browser' : platform.environment[_kTestBrowserKey],
+      if (platform.environment[_kTestBrowserKey] != null && platform.environment[_kWebRendererKey] == 'canvaskit')
+        'WebRenderer' : 'canvaskit',
       'CI' : 'luci',
       'Platform' : platform.operatingSystem,
       'name' : testName,

packages/flutter_tools/lib/src/build_system/targets/web.dart

@@ -404,17 +404,57 @@ class WebReleaseBundle extends Target {
   }
 }
 
+/// Static assets provided by the Flutter SDK that do not change, such as
+/// CanvasKit.
+///
+/// These assets can be cached forever and are only invalidated when the
+/// Flutter SDK is upgraded to a new version.
+class WebBuiltInAssets extends Target {
+  const WebBuiltInAssets(this.fileSystem);
+
+  final FileSystem fileSystem;
+
+  @override
+  String get name => 'web_static_assets';
+
+  @override
+  List<Target> get dependencies => const <Target>[];
+
+  @override
+  List<String> get depfiles => const <String>[];
+
+  @override
+  List<Source> get inputs => const <Source>[];
+
+  @override
+  List<Source> get outputs => const <Source>[];
+
+  @override
+  Future<void> build(Environment environment) async {
+    final Directory flutterWebSdk = globals.artifacts.getHostArtifact(HostArtifact.flutterWebSdk) as Directory;
+    final Directory canvasKitDirectory = flutterWebSdk.childDirectory('canvaskit');
+    for (final File file in canvasKitDirectory.listSync(recursive: true).whereType<File>()) {
+      final String relativePath = fileSystem.path.relative(file.path, from: canvasKitDirectory.path);
+      final String targetPath = fileSystem.path.join(environment.outputDir.path, 'canvaskit', relativePath);
+      file.copySync(targetPath);
+    }
+  }
+}
+
 /// Generate a service worker for a web target.
 class WebServiceWorker extends Target {
-  const WebServiceWorker();
+  const WebServiceWorker(this.fileSystem);
+
+  final FileSystem fileSystem;
 
   @override
   String get name => 'web_service_worker';
 
   @override
-  List<Target> get dependencies => const <Target>[
+  List<Target> get dependencies => <Target>[
-    Dart2JSTarget(),
+    const Dart2JSTarget(),
-    WebReleaseBundle(),
+    const WebReleaseBundle(),
+    WebBuiltInAssets(fileSystem),
   ];
 
   @override

packages/flutter_tools/lib/src/commands/assemble.dart

@@ -49,7 +49,7 @@ List<Target> _kDefaultTargets = <Target>[
   const ReleaseBundleLinuxAssets(TargetPlatform.linux_x64),
   const ReleaseBundleLinuxAssets(TargetPlatform.linux_arm64),
   // Web targets
-  const WebServiceWorker(),
+  WebServiceWorker(globals.fs),
   const ReleaseAndroidApplication(),
   // This is a one-off rule for bundle and aot compat.
   const CopyFlutterBundle(),

packages/flutter_tools/lib/src/flutter_cache.dart

@@ -196,6 +196,14 @@ class FlutterWebSdk extends CachedArtifact {
         entity.copySync(newPath);
       }
     }
+
+    final String canvasKitVersion = cache.getVersionFor('canvaskit')!;
+    final String canvasKitUrl = '$_cipdBaseUrl/flutter/web/canvaskit_bundle/+/$canvasKitVersion';
+    return artifactUpdater.downloadZipArchive(
+      'Downloading CanvasKit...',
+      Uri.parse(canvasKitUrl),
+      location,
+    );
   }
 }
 

packages/flutter_tools/lib/src/test/flutter_web_goldens.dart

@@ -15,6 +15,7 @@ import '../base/file_system.dart';
 import '../base/io.dart';
 import '../base/logger.dart';
 import '../convert.dart';
+import '../web/compile.dart';
 import 'test_compiler.dart';
 import 'test_config.dart';
 
@@ -31,6 +32,7 @@ class TestGoldenComparator {
     @required Logger logger,
     @required FileSystem fileSystem,
     @required ProcessManager processManager,
+    @required this.webRenderer,
   }) : tempDir = fileSystem.systemTempDirectory.createTempSync('flutter_web_platform.'),
        _logger = logger,
        _fileSystem = fileSystem,
@@ -42,6 +44,7 @@ class TestGoldenComparator {
   final Logger _logger;
   final FileSystem _fileSystem;
   final ProcessManager _processManager;
+  final WebRendererMode webRenderer;
 
   TestCompiler _compiler;
   TestGoldenComparatorProcess _previousComparator;
@@ -88,6 +91,7 @@ class TestGoldenComparator {
     final Map<String, String> environment = <String, String>{
       // Chrome is the only supported browser currently.
       'FLUTTER_TEST_BROWSER': 'chrome',
+      'FLUTTER_WEB_RENDERER': webRenderer == WebRendererMode.html ? 'html' : 'canvaskit',
     };
     return _processManager.start(command, environment: environment);
   }

packages/flutter_tools/lib/src/test/flutter_web_platform.dart

@@ -53,11 +53,13 @@ class FlutterWebPlatform extends PlatformPlugin {
     @required Logger logger,
     @required Artifacts artifacts,
     @required ProcessManager processManager,
+    @required Cache cache,
   }) : _fileSystem = fileSystem,
       _flutterToolPackageConfig = flutterToolPackageConfig,
       _chromiumLauncher = chromiumLauncher,
       _logger = logger,
-      _artifacts = artifacts {
+      _artifacts = artifacts,
+      _cache = cache {
     final shelf.Cascade cascade = shelf.Cascade()
         .add(_webSocketHandler.handler)
         .add(createStaticHandler(
@@ -65,6 +67,7 @@ class FlutterWebPlatform extends PlatformPlugin {
           serveFilesOutsidePath: true,
         ))
         .add(_handleStaticArtifact)
+        .add(_localCanvasKitHandler)
         .add(_goldenFileHandler)
         .add(_wrapperHandler)
         .add(_handleTestRequest)
@@ -80,6 +83,7 @@ class FlutterWebPlatform extends PlatformPlugin {
       fileSystem: _fileSystem,
       logger: _logger,
       processManager: processManager,
+      webRenderer: _rendererMode,
     );
   }
 
@@ -95,6 +99,7 @@ class FlutterWebPlatform extends PlatformPlugin {
   final OneOffHandler _webSocketHandler = OneOffHandler();
   final AsyncMemoizer<void> _closeMemo = AsyncMemoizer<void>();
   final String _root;
+  final Cache _cache;
 
   /// Allows only one test suite (typically one test file) to be loaded and run
   /// at any given point in time. Loading more than one file at a time is known
@@ -117,6 +122,7 @@ class FlutterWebPlatform extends PlatformPlugin {
     @required ChromiumLauncher chromiumLauncher,
     @required Artifacts artifacts,
     @required ProcessManager processManager,
+    @required Cache cache,
   }) async {
     final shelf_io.IOServer server = shelf_io.IOServer(await HttpMultiServer.loopback(0));
     final PackageConfig packageConfig = await loadPackageConfigWithLogging(
@@ -145,6 +151,7 @@ class FlutterWebPlatform extends PlatformPlugin {
       logger: logger,
       nullAssertions: nullAssertions,
       processManager: processManager,
+      cache: cache,
     );
   }
 
@@ -218,6 +225,23 @@ class FlutterWebPlatform extends PlatformPlugin {
     'host.dart.js',
   ));
 
+  File _canvasKitFile(String relativePath) {
+    // TODO(yjbanov): https://github.com/flutter/flutter/issues/52588
+    //
+    // Update this when we start building CanvasKit from sources. In the
+    // meantime, get the Web SDK directory from cache rather than through
+    // Artifacts. The latter is sensitive to `--local-engine`, which changes
+    // the directory to point to ENGINE/src/out. However, CanvasKit is not yet
+    // built as part of the engine, but fetched from CIPD, and so it won't be
+    // found in ENGINE/src/out.
+    final Directory webSdkDirectory = _cache.getWebSdkDirectory();
+    final File canvasKitFile = _fileSystem.file(_fileSystem.path.join(
+      webSdkDirectory.path,
+      relativePath,
+    ));
+    return canvasKitFile;
+  }
+
   Future<shelf.Response> _handleTestRequest(shelf.Request request) async {
     if (request.url.path.endsWith('.dart.browser_test.dart.js')) {
       final String leadingPath = request.url.path.split('.browser_test.dart.js')[0];
@@ -365,6 +389,37 @@ class FlutterWebPlatform extends PlatformPlugin {
     }
   }
 
+  /// Serves a local build of CanvasKit, replacing the CDN build, which can
+  /// cause test flakiness due to reliance on network.
+  shelf.Response _localCanvasKitHandler(shelf.Request request) {
+    final String path = _fileSystem.path.fromUri(request.url);
+    if (!path.startsWith('canvaskit/')) {
+      return shelf.Response.notFound('Not a CanvasKit file request');
+    }
+
+    final String extension = _fileSystem.path.extension(path);
+    String contentType;
+    switch (extension) {
+      case '.js':
+        contentType = 'text/javascript';
+        break;
+      case '.wasm':
+        contentType = 'application/wasm';
+        break;
+      default:
+        final String error = 'Failed to determine Content-Type for "${request.url.path}".';
+        _logger.printError(error);
+        return shelf.Response.internalServerError(body: error);
+    }
+
+    return shelf.Response.ok(
+      _canvasKitFile(path).openRead(),
+      headers: <String, Object>{
+        HttpHeaders.contentTypeHeader: contentType,
+      },
+    );
+  }
+
   // A handler that serves wrapper files used to bootstrap tests.
   shelf.Response _wrapperHandler(shelf.Request request) {
     final String path = _fileSystem.path.fromUri(request.url);
@@ -377,6 +432,11 @@ class FlutterWebPlatform extends PlatformPlugin {
         <html>
         <head>
           <title>${htmlEscape.convert(test)} Test</title>
+          <script>
+            window.flutterConfiguration = {
+              canvasKitBaseUrl: "/canvaskit/"
+            };
+          </script>
           $link
           <script src="static/dart.js"></script>
         </head>

packages/flutter_tools/lib/src/test/runner.dart

@@ -176,6 +176,7 @@ class _FlutterTestRunnerImpl implements FlutterTestRunner {
               browserFinder: findChromeExecutable,
               logger: globals.logger,
             ),
+            cache: globals.cache,
           );
         },
       );

packages/flutter_tools/lib/src/web/compile.dart

@@ -37,7 +37,7 @@ Future<void> buildWeb(
   final Status status = globals.logger.startProgress('Compiling $target for the Web...');
   final Stopwatch sw = Stopwatch()..start();
   try {
-    final BuildResult result = await globals.buildSystem.build(const WebServiceWorker(), Environment(
+    final BuildResult result = await globals.buildSystem.build(WebServiceWorker(globals.fs), Environment(
       projectDir: globals.fs.currentDirectory,
       outputDir: outputDirectory,
       buildDir: flutterProject.directory

packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart

@@ -637,7 +637,7 @@ void main() {
     environment.outputDir.childDirectory('a').childFile('a.txt')
       ..createSync(recursive: true)
       ..writeAsStringSync('A');
-    await const WebServiceWorker().build(environment);
+    await WebServiceWorker(globals.fs).build(environment);
 
     expect(environment.outputDir.childFile('flutter_service_worker.js'), exists);
     // Contains file hash.
@@ -656,7 +656,7 @@ void main() {
     environment.outputDir
       .childFile('index.html')
       .createSync(recursive: true);
-    await const WebServiceWorker().build(environment);
+    await WebServiceWorker(globals.fs).build(environment);
 
     expect(environment.outputDir.childFile('flutter_service_worker.js'), exists);
     // Contains file hash for both `/` and index.html.
@@ -674,7 +674,7 @@ void main() {
     environment.outputDir
       .childFile('main.dart.js.map')
       .createSync(recursive: true);
-    await const WebServiceWorker().build(environment);
+    await WebServiceWorker(globals.fs).build(environment);
 
     // No caching of source maps.
     expect(environment.outputDir.childFile('flutter_service_worker.js').readAsStringSync(),

packages/flutter_tools/test/general.shard/cache_test.dart

@@ -728,20 +728,49 @@ void main() {
     expect(logger.errorText, contains('Failed to delete some stamp files'));
   });
 
-  testWithoutContext('FlutterWebSdk deletes previous directory contents', () {
+  testWithoutContext('FlutterWebSdk fetches web artifacts and deletes previous directory contents', () async {
     final MemoryFileSystem fileSystem = MemoryFileSystem.test();
+    final File canvasKitVersionFile = fileSystem.currentDirectory
+      .childDirectory('cache')
+      .childDirectory('bin')
+      .childDirectory('internal')
+      .childFile('canvaskit.version');
+    canvasKitVersionFile.createSync(recursive: true);
+    canvasKitVersionFile.writeAsStringSync('abcdefg');
+
     final Cache cache = Cache.test(processManager: FakeProcessManager.any(), fileSystem: fileSystem);
     final Directory webCacheDirectory = cache.getWebSdkDirectory();
     final FakeArtifactUpdater artifactUpdater = FakeArtifactUpdater();
     final FlutterWebSdk webSdk = FlutterWebSdk(cache, platform: FakePlatform());
 
+    final List<String> messages = <String>[];
+    final List<String> downloads = <String>[];
+    final List<String> locations = <String>[];
     artifactUpdater.onDownloadZipArchive = (String message, Uri uri, Directory location) {
+      messages.add(message);
+      downloads.add(uri.toString());
+      locations.add(location.path);
       location.createSync(recursive: true);
       location.childFile('foo').createSync();
     };
     webCacheDirectory.childFile('bar').createSync(recursive: true);
 
-    webSdk.updateInner(artifactUpdater, fileSystem, FakeOperatingSystemUtils());
+    await webSdk.updateInner(artifactUpdater, fileSystem, FakeOperatingSystemUtils());
+
+    expect(messages, <String>[
+      'Downloading Web SDK...',
+      'Downloading CanvasKit...',
+    ]);
+
+    expect(downloads, <String>[
+      'https://storage.googleapis.com/flutter_infra_release/flutter/null/flutter-web-sdk-linux-x64.zip',
+      'https://chrome-infra-packages.appspot.com/dl/flutter/web/canvaskit_bundle/+/abcdefg',
+    ]);
+
+    expect(locations, <String>[
+      'cache/bin/cache/flutter_web_sdk',
+      'cache/bin/cache/flutter_web_sdk',
+    ]);
 
     expect(webCacheDirectory.childFile('foo'), exists);
     expect(webCacheDirectory.childFile('bar'), isNot(exists));

packages/flutter_tools/test/general.shard/web/golden_comparator_test.dart

@@ -13,6 +13,7 @@ import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/test/flutter_web_goldens.dart';
 import 'package:flutter_tools/src/test/test_compiler.dart';
+import 'package:flutter_tools/src/web/compile.dart';
 import 'package:test/fake.dart';
 
 import '../../src/common.dart';
@@ -45,7 +46,12 @@ void main() {
           '--non-interactive',
           '--packages=.dart_tool/package_config.json',
           'compiler_output'
-        ], stdout: '${jsonEncode(expectedResponse)}\n',
+        ],
+        stdout: '${jsonEncode(expectedResponse)}\n',
+        environment: const <String, String>{
+          'FLUTTER_TEST_BROWSER': 'chrome',
+          'FLUTTER_WEB_RENDERER': 'html',
+        },
       ));
 
       final TestGoldenComparator comparator = TestGoldenComparator(
@@ -54,6 +60,7 @@ void main() {
         processManager: processManager,
         fileSystem: MemoryFileSystem.test(),
         logger: BufferLogger.test(),
+        webRenderer: WebRendererMode.html,
       );
 
       final String result = await comparator.compareGoldens(testUri, imageBytes, goldenKey, false);
@@ -82,6 +89,7 @@ void main() {
         processManager: processManager,
         fileSystem: MemoryFileSystem.test(),
         logger: BufferLogger.test(),
+        webRenderer: WebRendererMode.canvaskit,
       );
 
       final String result = await comparator.compareGoldens(testUri, imageBytes, goldenKey, false);
@@ -114,6 +122,7 @@ void main() {
         processManager: processManager,
         fileSystem: MemoryFileSystem.test(),
         logger: BufferLogger.test(),
+        webRenderer: WebRendererMode.html,
       );
 
       final String result1 = await comparator.compareGoldens(testUri, imageBytes, goldenKey, false);
@@ -158,6 +167,7 @@ void main() {
         processManager: processManager,
         fileSystem: MemoryFileSystem.test(),
         logger: BufferLogger.test(),
+        webRenderer: WebRendererMode.canvaskit,
       );
 
       final String result1 = await comparator.compareGoldens(testUri, imageBytes, goldenKey, false);
@@ -192,6 +202,7 @@ void main() {
         processManager: processManager,
         fileSystem: fileSystem,
         logger: BufferLogger.test(),
+        webRenderer: WebRendererMode.html,
       );
 
       final String result = await comparator.compareGoldens(testUri, imageBytes, goldenKey, false);