Add integration tests for structured error (#59809)

packages/flutter_tools/test/integration.shard/flutter_run_with_error_test.dart

@@ -0,0 +1,69 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:file/file.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+
+import '../src/common.dart';
+import 'test_data/project_with_early_error.dart';
+import 'test_driver.dart';
+import 'test_utils.dart';
+
+void main() {
+  Directory tempDir;
+  final ProjectWithEarlyError _project = ProjectWithEarlyError();
+  const String _exceptionStart = '══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞══════════════════';
+  FlutterRunTestDriver _flutter;
+
+  setUp(() async {
+    tempDir = createResolvedTempDirectorySync('run_test.');
+    await _project.setUpIn(tempDir);
+    _flutter = FlutterRunTestDriver(tempDir);
+  });
+
+  tearDown(() async {
+    await _flutter.stop();
+    tryToDelete(tempDir);
+  });
+
+  test('flutter run reports an early error in an application', () async {
+    final StringBuffer stdout = StringBuffer();
+    _flutter.stdout.listen(stdout.writeln);
+
+    await _flutter.run(startPaused: true, withDebugger: true, structuredErrors: true);
+    await _flutter.resume();
+    await _flutter.stop();
+
+    expect(stdout.toString(), contains(_exceptionStart));
+  });
+
+  test('flutter run for web reports an early error in an application', () async {
+    final StringBuffer stdout = StringBuffer();
+
+    await _flutter.run(startPaused: true, withDebugger: true, structuredErrors: true, chrome: true);
+    await _flutter.resume();
+
+    final Completer<void> completer = Completer<void>();
+    bool lineFound = false;
+
+    await Future<void>(() async {
+      _flutter.stdout.listen((String line) {
+        stdout.writeln(line);
+        if (line.startsWith('Another exception was thrown') && !lineFound) {
+          lineFound = true;
+          completer.complete();
+        }
+      });
+      await completer.future;
+    }).timeout(const Duration(seconds: 15), onTimeout: () {
+      // Complete anyway in case we don't see the 'Another exception' line.
+      completer.complete();
+    });
+
+    expect(stdout.toString(), contains(_exceptionStart));
+    await _flutter.stop();
+  }, skip: 'Running in cirrus environment causes premature exit');
+}

packages/flutter_tools/test/integration.shard/test_data/project_with_early_error.dart

@@ -0,0 +1,41 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'project.dart';
+
+class ProjectWithEarlyError extends Project {
+
+  @override
+  final String pubspec = '''
+  name: test
+  environment:
+    sdk: ">=2.0.0-dev.68.0 <3.0.0"
+
+  dependencies:
+    flutter:
+      sdk: flutter
+  ''';
+
+  @override
+  final String main = r'''
+  import 'dart:async';
+
+  import 'package:flutter/material.dart';
+
+  Future<void> main() async {
+    while (true) {
+      runApp(new MyApp());
+      await Future.delayed(const Duration(milliseconds: 50));
+    }
+  }
+
+  class MyApp extends StatelessWidget {
+    @override
+    Widget build(BuildContext context) {
+      throw FormatException();
+    }
+  }
+  ''';
+
+}

packages/flutter_tools/test/integration.shard/test_driver.dart

@@ -437,6 +437,7 @@ class FlutterRunTestDriver extends FlutterTestDriver {
     bool startPaused = false,
     bool pauseOnExceptions = false,
     bool chrome = false,
+    bool structuredErrors = false,
     File pidFile,
     String script,
   }) async {
@@ -451,6 +452,8 @@ class FlutterRunTestDriver extends FlutterTestDriver {
           ...<String>['chrome', '--web-run-headless', '--web-enable-expression-evaluation']
         else
           'flutter-tester',
+        if (structuredErrors)
+          '--dart-define=flutter.inspector.structuredErrors=true',
       ],
       withDebugger: withDebugger,
       startPaused: startPaused,