Reland support flutter test on platform chrome (#33859)

packages/flutter_tools/build.yaml

 targets:
   $default:
+    builders:
+      build_web_compilers|entrypoint:
+        enabled: false
     sources:
       exclude:
         - "test/data/**"

packages/flutter_tools/lib/src/build_runner/web_compilation_delegate.dart

@@ -12,17 +12,21 @@ import 'package:build_modules/src/platform.dart';
 import 'package:build_runner_core/build_runner_core.dart' as core;
 import 'package:build_runner_core/src/generate/build_impl.dart';
 import 'package:build_runner_core/src/generate/options.dart';
+import 'package:build_test/builder.dart';
+import 'package:build_test/src/debug_test_builder.dart';
 import 'package:build_web_compilers/build_web_compilers.dart';
 import 'package:build_web_compilers/builders.dart';
 import 'package:build_web_compilers/src/dev_compiler_bootstrap.dart';
 import 'package:logging/logging.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
+import 'package:test_core/backend.dart';
 import 'package:watcher/watcher.dart';
 
 import '../artifacts.dart';
 import '../base/file_system.dart';
 import '../base/logger.dart';
+import '../base/platform.dart';
 import '../compile.dart';
 import '../dart/package_map.dart';
 import '../globals.dart';
@@ -65,6 +69,20 @@ final DartPlatform flutterWebPlatform =
 
 /// The build application to compile a flutter application to the web.
 final List<core.BuilderApplication> builders = <core.BuilderApplication>[
+  core.apply(
+    'flutter_tools|test_bootstrap',
+    <BuilderFactory>[
+      (BuilderOptions options) => const DebugTestBuilder(),
+      (BuilderOptions options) => const FlutterWebTestBootstrapBuilder(),
+    ],
+    core.toRoot(),
+    hideOutput: true,
+    defaultGenerateFor: const InputSet(
+      include: <String>[
+        'test/**',
+      ],
+    ),
+  ),
   core.apply(
       'flutter_tools|module_library',
       <Builder Function(BuilderOptions)>[moduleLibraryBuilder],
@@ -109,7 +127,7 @@ final List<core.BuilderApplication> builders = <core.BuilderApplication>[
     'flutter_tools|entrypoint',
     <BuilderFactory>[
       (BuilderOptions options) => FlutterWebEntrypointBuilder(
-          options.config['target'] ?? 'lib/main.dart'),
+          options.config['targets'] ?? <String>['lib/main.dart']),
     ],
     core.toRoot(),
     hideOutput: true,
@@ -117,6 +135,7 @@ final List<core.BuilderApplication> builders = <core.BuilderApplication>[
       include: <String>[
         'lib/**',
         'web/**',
+        'test/**_test.dart.browser_test.dart',
       ],
     ),
   ),
@@ -135,13 +154,14 @@ class BuildRunnerWebCompilationProxy extends WebCompilationProxy {
   @override
   Future<void> initialize({
     @required Directory projectDirectory,
-    @required String target,
+    @required List<String> targets,
+    String testOutputDir,
   }) async {
     // Override the generated output directory so this does not conflict with
     // other build_runner output.
     core.overrideGeneratedOutputDirectory('flutter_web');
     _packageUriMapper = PackageUriMapper(
-        path.absolute(target), PackageMap.globalPackagesPath, null, null);
+        path.absolute('lib/main.dart'), PackageMap.globalPackagesPath, null, null);
     _packageGraph = core.PackageGraph.forPath(projectDirectory.path);
     final core.BuildEnvironment buildEnvironment = core.OverrideableEnvironment(
         core.IOEnvironment(_packageGraph), onLog: (LogRecord record) {
@@ -163,8 +183,18 @@ class BuildRunnerWebCompilationProxy extends WebCompilationProxy {
       trackPerformance: false,
       deleteFilesByDefault: true,
     );
+    final Set<core.BuildDirectory> buildDirs = <core.BuildDirectory>{
+      if (testOutputDir != null)
+        core.BuildDirectory(
+          'test',
+          outputLocation: core.OutputLocation(
+            testOutputDir,
+            useSymlinks: !platform.isWindows,
+          ),
+      ),
+    };
     final Status status =
-        logger.startProgress('Compiling $target for the Web...', timeout: null);
+        logger.startProgress('Compiling ${targets.first} for the Web...', timeout: null);
     try {
       _builder = await BuildImpl.create(
         buildOptions,
@@ -172,12 +202,12 @@ class BuildRunnerWebCompilationProxy extends WebCompilationProxy {
         builders,
         <String, Map<String, dynamic>>{
           'flutter_tools|entrypoint': <String, dynamic>{
-            'target': target,
+            'targets': targets,
           }
         },
         isReleaseBuild: false,
       );
-      await _builder.run(const <AssetId, ChangeType>{});
+      await _builder.run(const <AssetId, ChangeType>{}, buildDirs: buildDirs);
     } finally {
       status.stop();
     }
@@ -205,9 +235,9 @@ class BuildRunnerWebCompilationProxy extends WebCompilationProxy {
 
 /// A ddc-only entrypoint builder that respects the Flutter target flag.
 class FlutterWebEntrypointBuilder implements Builder {
-  const FlutterWebEntrypointBuilder(this.target);
+  const FlutterWebEntrypointBuilder(this.targets);
 
-  final String target;
+  final List<String> targets;
 
   @override
   Map<String, List<String>> get buildExtensions => const <String, List<String>>{
@@ -222,10 +252,123 @@ class FlutterWebEntrypointBuilder implements Builder {
 
   @override
   Future<void> build(BuildStep buildStep) async {
-    if (!buildStep.inputId.path.contains(target)) {
+    bool matches = false;
+    for (String target in targets) {
+      if (buildStep.inputId.path.contains(target)) {
+        matches = true;
+        break;
+      }
+    }
+    if (!matches) {
       return;
     }
     log.info('building for target ${buildStep.inputId.path}');
     await bootstrapDdc(buildStep, platform: flutterWebPlatform);
   }
 }
+
+class FlutterWebTestBootstrapBuilder implements Builder {
+  const FlutterWebTestBootstrapBuilder();
+
+  @override
+  Map<String, List<String>> get buildExtensions => const <String, List<String>>{
+    '_test.dart': <String>[
+      '_test.dart.browser_test.dart',
+    ]
+  };
+
+  @override
+  Future<void> build(BuildStep buildStep) async {
+    final AssetId id = buildStep.inputId;
+    final String contents = await buildStep.readAsString(id);
+    final String assetPath = id.pathSegments.first == 'lib'
+        ? path.url.join('packages', id.package, id.path)
+        : id.path;
+    final Metadata metadata = parseMetadata(
+        assetPath, contents, Runtime.builtIn.map((Runtime runtime) => runtime.name).toSet());
+
+    if (metadata.testOn.evaluate(SuitePlatform(Runtime.chrome))) {
+    await buildStep.writeAsString(id.addExtension('.browser_test.dart'), '''
+import 'dart:ui' as ui;
+import 'dart:html';
+import 'dart:js';
+
+import 'package:stream_channel/stream_channel.dart';
+import 'package:test_api/src/backend/stack_trace_formatter.dart'; // ignore: implementation_imports
+import 'package:test_api/src/util/stack_trace_mapper.dart'; // ignore: implementation_imports
+import 'package:test_api/src/remote_listener.dart'; // ignore: implementation_imports
+import 'package:test_api/src/suite_channel_manager.dart'; // ignore: implementation_imports
+
+import "${path.url.basename(id.path)}" as test;
+
+Future<void> main() async {
+  // Extra initialization for flutter_web.
+  // The following parameters are hard-coded in Flutter's test embedder. Since
+  // we don't have an embedder yet this is the lowest-most layer we can put
+  // this stuff in.
+  await ui.webOnlyInitializeEngine();
+  internalBootstrapBrowserTest(() => test.main);
+}
+
+void internalBootstrapBrowserTest(Function getMain()) {
+  var channel =
+      serializeSuite(getMain, hidePrints: false, beforeLoad: () async {
+    var serialized =
+        await suiteChannel("test.browser.mapper").stream.first as Map;
+    if (serialized == null) return;
+  });
+  postMessageChannel().pipe(channel);
+}
+StreamChannel serializeSuite(Function getMain(),
+        {bool hidePrints = true, Future beforeLoad()}) =>
+    RemoteListener.start(getMain,
+        hidePrints: hidePrints, beforeLoad: beforeLoad);
+
+StreamChannel suiteChannel(String name) {
+  var manager = SuiteChannelManager.current;
+  if (manager == null) {
+    throw StateError('suiteChannel() may only be called within a test worker.');
+  }
+
+  return manager.connectOut(name);
+}
+
+StreamChannel postMessageChannel() {
+  var controller = StreamChannelController(sync: true);
+  window.onMessage.firstWhere((message) {
+    return message.origin == window.location.origin && message.data == "port";
+  }).then((message) {
+    var port = message.ports.first;
+    var portSubscription = port.onMessage.listen((message) {
+      controller.local.sink.add(message.data);
+    });
+
+    controller.local.stream.listen((data) {
+      port.postMessage({"data": data});
+    }, onDone: () {
+      port.postMessage({"event": "done"});
+      portSubscription.cancel();
+    });
+  });
+
+  context['parent'].callMethod('postMessage', [
+    JsObject.jsify({"href": window.location.href, "ready": true}),
+    window.location.origin,
+  ]);
+  return controller.foreign;
+}
+
+void setStackTraceMapper(StackTraceMapper mapper) {
+  var formatter = StackTraceFormatter.current;
+  if (formatter == null) {
+    throw StateError(
+        'setStackTraceMapper() may only be called within a test worker.');
+  }
+
+  formatter.configure(mapper: mapper);
+}
+''');
+    }
+  }
+}
+

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

@@ -99,6 +99,11 @@ class TestCommand extends FastFlutterCommand {
         negatable: true,
         help: 'Whether to build the assets bundle for testing.\n'
               'Consider using --no-test-assets if assets are not required.',
+      )
+      ..addOption('platform',
+        allowed: const <String>['tester', 'chrome'],
+        defaultsTo: 'tester',
+        help: 'The platform to run the unit tests on. Defaults to "tester".'
       );
   }
 
@@ -166,6 +171,16 @@ class TestCommand extends FastFlutterCommand {
             'Test files must be in that directory and end with the pattern "_test.dart".'
         );
       }
+    } else {
+      final List<String> fileCopy = <String>[];
+      for (String file in files) {
+        if (file.endsWith(platform.pathSeparator)) {
+          fileCopy.addAll(_findTests(fs.directory(file)));
+        } else {
+          fileCopy.add(file);
+        }
+      }
+      files = fileCopy;
     }
 
     CoverageCollector collector;
@@ -222,6 +237,7 @@ class TestCommand extends FastFlutterCommand {
       concurrency: jobs,
       buildTestAssets: buildTestAssets,
       flutterProject: flutterProject,
+      web: argResults['platform'] == 'chrome',
     );
 
     if (collector != null) {

packages/flutter_tools/lib/src/resident_web_runner.dart

@@ -120,7 +120,7 @@ class ResidentWebRunner extends ResidentRunner {
     // Start the web compiler and build the assets.
     await webCompilationProxy.initialize(
       projectDirectory: currentProject.directory,
-      target: target,
+      targets: <String>[target],
     );
     _lastCompiled = DateTime.now();
     final AssetBundle assetBundle = AssetBundleFactory.instance.createBundle();

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

@@ -5,7 +5,9 @@
 import 'dart:async';
 
 import 'package:meta/meta.dart';
+import 'package:test_api/backend.dart';
 import 'package:test_core/src/executable.dart' as test; // ignore: implementation_imports
+import 'package:test_core/src/runner/hack_register_platform.dart' as hack; // ignore: implementation_imports
 
 import '../artifacts.dart';
 import '../base/common.dart';
@@ -16,7 +18,9 @@ import '../base/terminal.dart';
 import '../dart/package_map.dart';
 import '../globals.dart';
 import '../project.dart';
+import '../web/compile.dart';
 import 'flutter_platform.dart' as loader;
+import 'flutter_web_platform.dart';
 import 'watcher.dart';
 
 /// Runs tests using package:test and the Flutter engine.
@@ -40,6 +44,7 @@ Future<int> runTests(
   FlutterProject flutterProject,
   String icudtlPath,
   Directory coverageDirectory,
+  bool web = false,
 }) async {
   // Compute the command-line arguments for package:test.
   final List<String> testArgs = <String>[];
@@ -62,6 +67,32 @@ Future<int> runTests(
   for (String plainName in plainNames) {
     testArgs..add('--plain-name')..add(plainName);
   }
+  if (web) {
+    final String tempBuildDir = fs.systemTempDirectory
+      .createTempSync('_flutter_test')
+      .absolute
+      .uri
+      .toFilePath();
+    await webCompilationProxy.initialize(
+      projectDirectory: flutterProject.directory,
+      testOutputDir: tempBuildDir,
+      targets: testFiles.map((String testFile) {
+        return fs.path.relative(testFile, from: flutterProject.directory.path);
+      }).toList(),
+    );
+    testArgs.add('--platform=chrome');
+    testArgs.add('--precompiled=$tempBuildDir');
+    testArgs.add('--');
+    testArgs.addAll(testFiles);
+    hack.registerPlatformPlugin(
+      <Runtime>[Runtime.chrome],
+      () {
+        return FlutterWebPlatform.start(flutterProject.directory.path);
+      }
+    );
+    await test.main(testArgs);
+    return exitCode;
+  }
 
   testArgs.add('--');
   testArgs.addAll(testFiles);

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

@@ -73,7 +73,10 @@ class ChromeLauncher {
   static final Completer<Chrome> _currentCompleter = Completer<Chrome>();
 
   /// Launch the chrome browser to a particular `host` page.
-  Future<Chrome> launch(String url) async {
+  ///
+  /// `headless` defaults to false, and controls whether we open a headless or
+  /// a `headfull` browser.
+  Future<Chrome> launch(String url, { bool headless = false }) async {
     final String chromeExecutable = findChromeExecutable();
     final Directory dataDir = fs.systemTempDirectory.createTempSync();
     final int port = await os.findFreePort();
@@ -94,6 +97,8 @@ class ChromeLauncher {
       '--no-default-browser-check',
       '--disable-default-apps',
       '--disable-translate',
+      if (headless)
+        ...<String>['--headless', '--disable-gpu'],
       url,
     ];
     final Process process = await processManager.start(args);
@@ -107,12 +112,14 @@ class ChromeLauncher {
           throwToolExit('Unable to connect to Chrome DevTools.');
           return null;
         });
+    final Uri remoteDebuggerUri = await _getRemoteDebuggerUrl(Uri.parse('http://localhost:$port'));
 
     return _connect(Chrome._(
       port,
       ChromeConnection('localhost', port),
       process: process,
       dataDir: dataDir,
+      remoteDebuggerUri: remoteDebuggerUri,
     ));
   }
 
@@ -138,15 +145,36 @@ class ChromeLauncher {
       _connect(Chrome._(port, ChromeConnection('localhost', port)));
 
   static Future<Chrome> get connectedInstance => _currentCompleter.future;
+
+  /// Returns the full URL of the Chrome remote debugger for the main page.
+///
+/// This takes the [base] remote debugger URL (which points to a browser-wide
+/// page) and uses its JSON API to find the resolved URL for debugging the host
+/// page.
+Future<Uri> _getRemoteDebuggerUrl(Uri base) async {
+  try {
+    final HttpClient client = HttpClient();
+    final HttpClientRequest request = await client.getUrl(base.resolve('/json/list'));
+    final HttpClientResponse response = await request.close();
+    final List<dynamic> jsonObject = await json.fuse(utf8).decoder.bind(response).single;
+    return base.resolve(jsonObject.first['devtoolsFrontendUrl']);
+  } catch (_) {
+    // If we fail to talk to the remote debugger protocol, give up and return
+    // the raw URL rather than crashing.
+    return base;
+  }
+}
+
 }
 
 /// A class for managing an instance of Chrome.
 class Chrome {
-  const Chrome._(
+  Chrome._(
     this.debugPort,
     this.chromeConnection, {
     Process process,
     Directory dataDir,
+    this.remoteDebuggerUri,
   })  : _process = process,
         _dataDir = dataDir;
 
@@ -154,15 +182,18 @@ class Chrome {
   final Process _process;
   final Directory _dataDir;
   final ChromeConnection chromeConnection;
+  final Uri remoteDebuggerUri;
 
   static Completer<Chrome> _currentCompleter = Completer<Chrome>();
 
+  Future<void> get onExit => _currentCompleter.future;
+
   Future<void> close() async {
     if (_currentCompleter.isCompleted) {
       _currentCompleter = Completer<Chrome>();
     }
     chromeConnection.close();
-    _process?.kill(ProcessSignal.SIGKILL);
+    _process?.kill();
     await _process?.exitCode;
     try {
       // Chrome starts another process as soon as it dies that modifies the

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

@@ -91,7 +91,8 @@ class WebCompilationProxy {
   /// `projectDirectory`.
   Future<void> initialize({
     @required Directory projectDirectory,
-    @required String target,
+    @required List<String> targets,
+    String testOutputDir,
   }) async {
     throw UnimplementedError();
   }

packages/flutter_tools/static/index.html

+<!DOCTYPE html>
+<html>
+<head>
+  <title>test Browser Host</title>
+</head>
+<body>
+  <svg id="dart" version="1.1" x="0px" y="0px" width="400px" height="400px" viewBox="0 0 400 400">
+    <path id="right-flank" fill="#0083C9" d="M249.379,226.486l-6.676,15.572L166.174,166h58.82c0,0,2.807-0.409,3.645,1.966L249.379,226.486z"/>
+    <path id="right-ear"   fill="#00D2B8" d="M201.84,141.906L166.174,166h58.82c0,0,2.168-0.25,2.645,0.566l-2.694-8.848l-15.024-14.68C207.555,140.329,203.578,140.744,201.84,141.906z"/>
+    <path id="left-flank"  fill="#00D2B8" d="M242.616,241.856l-15.022,6.799l-60.493-21.429c-1.035-0.395-1.101-3.696-1.101-3.696v-57.932L242.616,241.856z"/>
+    <path id="left-paw"    fill="#55DECA" d="M167.003,227.098l60.636,21.558l15.064-6.799L237.224,259h-43.856c0,0-14.077-13.929-18.141-17.993C171.162,236.943,169.162,233.989,167.003,227.098z"/>
+    <path id="right-paw"   fill="#00A4E4" d="M227.676,166.365c0.963,1.401,1.361,2.473,1.361,2.473l20.352,57.648l-6.711,15.37L259,236.463v-44.854c0,0-13.678-13.965-17.741-17.882C237.193,169.811,231.466,166.319,227.676,166.365z"/>
+    <path id="left-ear"    fill="#0083C9" d="M166.769,227.098c0,0-0.769-1.104-0.769-4.355v-57.144l-23.115,34.877c-1.626,1.774-1.567,6.538,1.595,9.755l13.636,13.892L166.769,227.098z"/>
+  </svg>
+  <div id="dark"></div>
+  <svg id="play" version="1.1" x="0px" y="0px" width="80px" height="80px" viewBox="0 0 25 25">
+    <defs><filter id="blur"><feGaussianBlur stdDeviation="0.3" id="feGaussianBlur5097" /></filter></defs>
+    <path d="M 3.777014,1.3715789 A 1.1838119,1.1838119 0 0 0 2.693923,2.5488509 V 22.444746 a 1.1838119,1.1838119 0 0 0 1.765908,1.035999 l 17.235259,-9.95972 a 1.1838119,1.1838119 0 0 0 0,-2.071998 L 4.459831,1.5128519 A 1.1838119,1.1838119 0 0 0 3.777014,1.3715789 z" style="opacity:0.5;stroke:#000000;stroke-width:1;filter:url(#blur)" />
+    <path style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:1.32722104" d="M 3.4770491,1.0714664 A 1.1838119,1.1838119 0 0 0 2.3939589,2.2487382 V 22.144633 a 1.1838119,1.1838119 0 0 0 1.7659079,1.035999 l 17.2352602,-9.95972 a 1.1838119,1.1838119 0 0 0 0,-2.071998 L 4.1598668,1.2127389 A 1.1838119,1.1838119 0 0 0 3.4770491,1.0714664 z" />
+  </svg>
+  <script src="host.dart.js"></script>
+</body>
+</html>