[flutter_tools] use temp dir for tester dill, use desktop log reader (#75922)

On windows, its not possible to run 2 integration tests using flutter-tester simultaneously. This is due to the flutter tester using a fixed location for its dill output. Use a temp dir instead.

Also replace the custom log reader in flutter-tester with the desktop log reader, and ensure stopApp waits for the process exit code.

Fixes #75534

packages/flutter_tools/lib/src/tester/flutter_tester.dart

@@ -18,7 +18,7 @@ import '../base/logger.dart';
 import '../base/os.dart';
 import '../build_info.dart';
 import '../bundle.dart';
-import '../convert.dart';
+import '../desktop_device.dart';
 import '../devfs.dart';
 import '../device.dart';
 import '../project.dart';
@@ -53,14 +53,15 @@ class FlutterTesterDevice extends Device {
     @required ProcessManager processManager,
     @required FlutterVersion flutterVersion,
     @required Logger logger,
-    @required String buildDirectory,
+    // TODO(jonahwilliams): remove once g3 rolls.
+    // ignore: avoid_unused_constructor_parameters
+    String buildDirectory,
     @required FileSystem fileSystem,
     @required Artifacts artifacts,
     @required OperatingSystemUtils operatingSystemUtils,
   }) : _processManager = processManager,
        _flutterVersion = flutterVersion,
        _logger = logger,
-       _buildDirectory = buildDirectory,
        _fileSystem = fileSystem,
        _artifacts = artifacts,
        _operatingSystemUtils = operatingSystemUtils,
@@ -74,7 +75,6 @@ class FlutterTesterDevice extends Device {
   final ProcessManager _processManager;
   final FlutterVersion _flutterVersion;
   final Logger _logger;
-  final String _buildDirectory;
   final FileSystem _fileSystem;
   final Artifacts _artifacts;
   final OperatingSystemUtils _operatingSystemUtils;
@@ -109,8 +109,7 @@ class FlutterTesterDevice extends Device {
   @override
   void clearLogs() { }
 
-  final _FlutterTesterDeviceLogReader _logReader =
-      _FlutterTesterDeviceLogReader();
+  final DesktopLogReader _logReader = DesktopLogReader();
 
   @override
   DeviceLogReader getLogReader({
@@ -155,11 +154,13 @@ class FlutterTesterDevice extends Device {
       return LaunchResult.failed();
     }
 
-    final String assetDirPath = _fileSystem.path.join(_buildDirectory, 'flutter_assets');
+    final Directory assetDirectory = _fileSystem.systemTempDirectory
+      .createTempSync('flutter-tester');
     final String applicationKernelFilePath = getKernelPathForTransformerOptions(
-      _fileSystem.path.join(_buildDirectory, 'flutter-tester-app.dill'),
+      _fileSystem.path.join(assetDirectory.path, 'flutter-tester-app.dill'),
       trackWidgetCreation: buildInfo.trackWidgetCreation,
     );
+
     // Build assets and perform initial compilation.
     await BundleBuilder().build(
       buildInfo: buildInfo,
@@ -168,6 +169,7 @@ class FlutterTesterDevice extends Device {
       trackWidgetCreation: buildInfo.trackWidgetCreation,
       platform: getTargetPlatformForName(getNameForHostPlatform(_operatingSystemUtils.hostPlatform)),
       treeShakeIcons: buildInfo.treeShakeIcons,
+      assetDirPath: assetDirectory.path,
     );
 
     final List<String> command = <String>[
@@ -176,7 +178,7 @@ class FlutterTesterDevice extends Device {
       '--non-interactive',
       '--enable-dart-profiling',
       '--packages=${debuggingOptions.buildInfo.packagesPath}',
-      '--flutter-assets-dir=$assetDirPath',
+      '--flutter-assets-dir=${assetDirectory.path}',
       if (debuggingOptions.startPaused)
         '--start-paused',
       if (debuggingOptions.disableServiceAuthCodes)
@@ -194,15 +196,6 @@ class FlutterTesterDevice extends Device {
           'FLUTTER_TEST': 'true',
         },
       );
-      _process.stdout
-        .transform<String>(utf8.decoder)
-        .transform<String>(const LineSplitter())
-        .listen(_logReader.addLine);
-      _process.stderr
-        .transform<String>(utf8.decoder)
-        .transform<String>(const LineSplitter())
-        .listen(_logReader.addLine);
-
       if (!debuggingOptions.debuggingEnabled) {
         return LaunchResult.succeeded();
       }
@@ -213,6 +206,7 @@ class FlutterTesterDevice extends Device {
         devicePort: debuggingOptions.deviceVmServicePort,
         ipv6: ipv6,
       );
+      _logReader.initializeProcess(_process);
 
       final Uri observatoryUri = await observatoryDiscovery.uri;
       if (observatoryUri != null) {
@@ -273,14 +267,15 @@ class FlutterTesterDevices extends PollingDeviceDiscovery {
     @required ProcessManager processManager,
     @required Logger logger,
     @required FlutterVersion flutterVersion,
-    @required Config config,
+    // TODO(jonahwilliams): remove after flutter rolls
+    // ignore: avoid_unused_constructor_parameters
+    Config config,
     @required OperatingSystemUtils operatingSystemUtils,
   }) : _testerDevice = FlutterTesterDevice(
         kTesterDeviceId,
         fileSystem: fileSystem,
         artifacts: artifacts,
         processManager: processManager,
-        buildDirectory: getBuildDirectory(config, fileSystem),
         logger: logger,
         flutterVersion: flutterVersion,
         operatingSystemUtils: operatingSystemUtils,
@@ -304,22 +299,3 @@ class FlutterTesterDevices extends PollingDeviceDiscovery {
     return showFlutterTesterDevice ? <Device>[_testerDevice] : <Device>[];
   }
 }
-
-class _FlutterTesterDeviceLogReader extends DeviceLogReader {
-  final StreamController<String> _logLinesController =
-      StreamController<String>.broadcast();
-
-  @override
-  int get appPid => 0;
-
-  @override
-  Stream<String> get logLines => _logLinesController.stream;
-
-  @override
-  String get name => 'flutter tester log reader';
-
-  void addLine(String line) => _logLinesController.add(line);
-
-  @override
-  void dispose() {}
-}

packages/flutter_tools/test/general.shard/tester/flutter_tester_test.dart

@@ -4,6 +4,8 @@
 
 // @dart = 2.8
 
+import 'dart:async';
+
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/artifacts.dart';
@@ -149,18 +151,18 @@ void main() {
     testUsingContext('performs a build and starts in debug mode', () async {
       final FlutterTesterApp app = FlutterTesterApp.fromCurrentDirectory(fileSystem);
       final Uri observatoryUri = Uri.parse('http://127.0.0.1:6666/');
-      final String assetsPath = fileSystem.path.join('build', 'flutter_assets');
-      final String dillPath = fileSystem.path.join('build', 'flutter-tester-app.dill');
+      final Completer<void> completer = Completer<void>();
       fakeProcessManager.addCommand(FakeCommand(
-        command: <String>[
+        command: const <String>[
           'Artifact.flutterTester',
           '--run-forever',
           '--non-interactive',
           '--enable-dart-profiling',
           '--packages=.packages',
-          '--flutter-assets-dir=$assetsPath',
-          dillPath,
+          '--flutter-assets-dir=/.tmp_rand0/flutter-testerrand0',
+          '/.tmp_rand0/flutter-testerrand0/flutter-tester-app.dill',
         ],
+        completer: completer,
         stdout:
         '''
 Observatory listening on $observatoryUri