[flutter_tools] support machine and coverage together but for real (#54692)

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

@@ -177,6 +177,12 @@ class CoverageCollector extends TestWatcher {
     }
     return true;
   }
+
+  @override
+  Future<void> handleTestCrashed(ProcessEvent event) async { }
+
+  @override
+  Future<void> handleTestTimedOut(ProcessEvent event) async { }
 }
 
 Future<VMService> _defaultConnect(Uri serviceUri) {

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

@@ -22,6 +22,21 @@ class EventPrinter extends TestWatcher {
     _parent?.handleStartedProcess(event);
   }
 
+  @override
+  Future<void> handleTestCrashed(ProcessEvent event) async {
+    return _parent.handleTestCrashed(event);
+  }
+
+  @override
+  Future<void> handleTestTimedOut(ProcessEvent event) async {
+    return _parent.handleTestTimedOut(event);
+  }
+
+  @override
+  Future<void> handleFinishedTest(ProcessEvent event) async {
+    return _parent.handleFinishedTest(event);
+  }
+
   void _sendEvent(String name, [ dynamic params ]) {
     final Map<String, dynamic> map = <String, dynamic>{'event': name};
     if (params != null) {

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

@@ -17,14 +17,14 @@ abstract class TestWatcher {
   ///
   /// The child process won't exit until this method completes.
   /// Not called if the process died.
-  Future<void> handleFinishedTest(ProcessEvent event) async { }
+  Future<void> handleFinishedTest(ProcessEvent event);
 
   /// Called when the test process crashed before connecting to test harness.
-  Future<void> handleTestCrashed(ProcessEvent event) async { }
+  Future<void> handleTestCrashed(ProcessEvent event);
 
   /// Called if we timed out waiting for the test process to connect to test
   /// harness.
-  Future<void> handleTestTimedOut(ProcessEvent event) async { }
+  Future<void> handleTestTimedOut(ProcessEvent event);
 }
 
 /// Describes a child process started during testing.

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

@@ -0,0 +1,35 @@
+// 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 'package:file/file.dart';
+import 'package:file_testing/file_testing.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+
+import '../src/common.dart';
+
+import 'test_data/test_project.dart';
+import 'test_driver.dart';
+import 'test_utils.dart';
+
+void main() {
+  Directory tempDir;
+
+  setUp(() async {
+    tempDir = createResolvedTempDirectorySync('flutter_coverage_collection_test.');
+  });
+
+  tearDown(() async {
+    tryToDelete(tempDir);
+  });
+
+  test('Can collect coverage in machine mode', () async {
+    final TestProject project = TestProject();
+    await project.setUpIn(tempDir);
+    final FlutterTestTestDriver flutter = FlutterTestTestDriver(tempDir);
+    await flutter.test(coverage: true);
+    await flutter.done;
+
+    expect(tempDir.childDirectory('coverage').childFile('lcov.info'), exists);
+  });
+}

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

@@ -26,6 +26,7 @@ abstract class Project {
 
   String get pubspec;
   String get main;
+  String get test => null;
 
   Uri get mainDart => Uri.parse('package:test/main.dart');
 
@@ -35,6 +36,9 @@ abstract class Project {
     if (main != null) {
       writeFile(globals.fs.path.join(dir.path, 'lib', 'main.dart'), main);
     }
+    if (test != null) {
+      writeFile(globals.fs.path.join(dir.path, 'test', 'test.dart'), test);
+    }
     writeFile(globals.fs.path.join(dir.path, 'web', 'index.html'), _kDefaultHtml);
     await getPackages(dir.path);
   }

packages/flutter_tools/test/integration.shard/test_data/test_project.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 TestProject extends Project {
+
+  @override
+  final String pubspec = '''
+  name: test
+  environment:
+    sdk: ">=2.0.0-dev.68.0 <3.0.0"
+
+  dependencies:
+    flutter:
+      sdk: flutter
+  dev_dependencies:
+    flutter_test:
+      sdk: flutter
+  ''';
+
+  @override
+  final String main = r'''
+int foo(int bar) {
+  return bar + 2;
+}
+  ''';
+
+  @override
+  final String test = r'''
+  import 'package:flutter_test/flutter_test.dart';
+  import 'package:test/main.dart';
+
+  void main() {
+    testWidgets('it can test', (WidgetTester tester) async {
+      expect(foo(2), 4);
+    });
+  }
+''';
+}

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

@@ -126,6 +126,8 @@ abstract class FlutterTestDriver {
     _stderr.stream.listen((String message) => _debugPrint(message, topic: '<=stderr='));
   }
 
+  Future<void> get done => _process.exitCode;
+
   Future<void> connectToVmService({ bool pauseOnExceptions = false }) async {
     _vmService = await vmServiceConnectUri('$_vmServiceWsUri');
     _vmService.onSend.listen((String s) => _debugPrint(s, topic: '=vm=>'));
@@ -680,6 +682,7 @@ class FlutterTestTestDriver extends FlutterTestDriver {
     String testFile = 'test/test.dart',
     bool withDebugger = false,
     bool pauseOnExceptions = false,
+    bool coverage = false,
     File pidFile,
     Future<void> Function() beforeStart,
   }) async {
@@ -687,6 +690,8 @@ class FlutterTestTestDriver extends FlutterTestDriver {
       'test',
       '--disable-service-auth-codes',
       '--machine',
+      if (coverage)
+        '--coverage',
     ], script: testFile, withDebugger: withDebugger, pauseOnExceptions: pauseOnExceptions, pidFile: pidFile, beforeStart: beforeStart);
   }