Catch unable to start app exception (#154970)

Fixes https://github.com/flutter/flutter/issues/153433

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

@@ -11,6 +11,7 @@ import 'package:package_config/package_config.dart';
 import 'package:stream_channel/stream_channel.dart';
 import 'package:test_core/src/platform.dart'; // ignore: implementation_imports
 
+import '../base/async_guard.dart';
 import '../base/common.dart';
 import '../base/file_system.dart';
 import '../base/io.dart';
@@ -459,6 +460,15 @@ class FlutterPlatform extends PlatformPlugin {
     );
   }
 
+  void _handleStartedDevice(Uri? uri, int testCount) {
+    if (uri != null) {
+      globals.printTrace('test $testCount: VM Service uri is available at $uri');
+    } else {
+      globals.printTrace('test $testCount: VM Service uri is not available');
+    }
+    watcher?.handleStartedDevice(uri);
+  }
+
   Future<_AsyncError?> _startTest(
     String testPath,
     StreamChannel<dynamic> testHarnessChannel,
@@ -530,7 +540,16 @@ class FlutterPlatform extends PlatformPlugin {
       globals.printTrace('test $ourTestCount: starting test device');
       final TestDevice testDevice = _createTestDevice(ourTestCount);
       final Stopwatch? testTimeRecorderStopwatch = testTimeRecorder?.start(TestTimePhases.Run);
-      final Future<StreamChannel<String>> remoteChannelFuture = testDevice.start(mainDart!);
+      final Completer<StreamChannel<String>> remoteChannelCompleter = Completer<StreamChannel<String>>();
+      unawaited(asyncGuard(
+        () async {
+          final StreamChannel<String> channel = await testDevice.start(mainDart!);
+          remoteChannelCompleter.complete(channel);
+        },
+        onError: (Object err, StackTrace stackTrace) {
+          remoteChannelCompleter.completeError(err, stackTrace);
+        },
+      ));
       finalizers.add(() async {
         globals.printTrace('test $ourTestCount: ensuring test device is terminated.');
         await testDevice.kill();
@@ -545,15 +564,21 @@ class FlutterPlatform extends PlatformPlugin {
       await Future.any<void>(<Future<void>>[
         testDevice.finished,
         () async {
-          final Uri? processVmServiceUri = await testDevice.vmServiceUri;
-          if (processVmServiceUri != null) {
-            globals.printTrace('test $ourTestCount: VM Service uri is available at $processVmServiceUri');
-          } else {
-            globals.printTrace('test $ourTestCount: VM Service uri is not available');
-          }
-          watcher?.handleStartedDevice(processVmServiceUri);
+          final [Object? first, Object? _] = await Future.wait<Object?>(
+            <Future<Object?>>[
+              // This future may depend on [_handleStartedDevice] having been called
+              remoteChannelCompleter.future,
+              testDevice.vmServiceUri.then<void>((Uri? processVmServiceUri) {
+                _handleStartedDevice(processVmServiceUri, ourTestCount);
+              }),
+            ],
+            // If [remoteChannelCompleter.future] errors, we may never get the
+            // VM service URI, so erroring eagerly is necessary to avoid a
+            // deadlock.
+            eagerError: true,
+          );
+          final StreamChannel<String> remoteChannel = first! as StreamChannel<String>;
 
-          final StreamChannel<String> remoteChannel = await remoteChannelFuture;
           globals.printTrace('test $ourTestCount: connected to test device, now awaiting test result');
 
           await _pipeHarnessToRemote(

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

@@ -3,11 +3,17 @@
 // found in the LICENSE file.
 
 import 'package:file/memory.dart';
+import 'package:flutter_tools/src/application_package.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/device.dart';
+import 'package:flutter_tools/src/flutter_manifest.dart';
+import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:flutter_tools/src/project.dart';
 import 'package:flutter_tools/src/test/flutter_platform.dart';
+import 'package:test/fake.dart';
 import 'package:test_core/backend.dart';
 
 import '../src/common.dart';
@@ -63,6 +69,34 @@ void main() {
       ProcessManager: () => FakeProcessManager.any(),
     });
 
+    testUsingContext('an exception from the app not starting bubbles up to the test runner', () async {
+      final _UnstartableDevice testDevice = _UnstartableDevice();
+      final FlutterPlatform flutterPlatform = FlutterPlatform(
+        debuggingOptions: DebuggingOptions.enabled(BuildInfo.debug),
+        shellPath: '/',
+        enableVmService: false,
+        integrationTestDevice: testDevice,
+        flutterProject: _FakeFlutterProject(),
+        host: InternetAddress.anyIPv4,
+        updateGoldens: false,
+      );
+
+      await expectLater(
+        () => flutterPlatform.loadChannel('test1.dart', fakeSuitePlatform).stream.drain<void>(),
+        // we intercept the actual exception and throw a string for the test runner to catch
+        throwsA(isA<String>().having(
+          (String msg) => msg,
+          'string',
+          'Unable to start the app on the device.',
+        )),
+      );
+      expect((globals.logger as BufferLogger).traceText, contains('test 0: error caught during test;'));
+    }, overrides: <Type, Generator>{
+      FileSystem: () => fileSystem,
+      ProcessManager: () => FakeProcessManager.any(),
+      ApplicationPackageFactory: () => _FakeApplicationPackageFactory(),
+    });
+
     testUsingContext('installHook creates a FlutterPlatform', () {
       expect(() => installHook(
         shellPath: 'abc',
@@ -158,3 +192,44 @@ void main() {
     });
   });
 }
+
+class _UnstartableDevice extends Fake implements Device {
+  @override
+  Future<void> dispose() => Future<void>.value();
+
+  @override
+  Future<TargetPlatform> get targetPlatform => Future<TargetPlatform>.value(TargetPlatform.android);
+
+  @override
+  Future<bool> stopApp(ApplicationPackage? app, {String? userIdentifier}) async {
+    return true;
+  }
+
+  @override
+  Future<bool> uninstallApp(ApplicationPackage app, {String? userIdentifier}) async => true;
+
+  @override
+  Future<LaunchResult> startApp(covariant ApplicationPackage? package, {String? mainPath, String? route, required DebuggingOptions debuggingOptions, Map<String, Object?> platformArgs = const <String, Object>{}, bool prebuiltApplication = false, String? userIdentifier}) async {
+    return LaunchResult.failed();
+  }
+}
+
+class _FakeFlutterProject extends Fake implements FlutterProject {
+  @override
+  FlutterManifest get manifest => FlutterManifest.empty(logger: BufferLogger.test());
+}
+
+class _FakeApplicationPackageFactory implements ApplicationPackageFactory {
+  TargetPlatform? platformRequested;
+  File? applicationBinaryRequested;
+  ApplicationPackage applicationPackage = _FakeApplicationPackage();
+
+  @override
+  Future<ApplicationPackage?> getPackageForPlatform(TargetPlatform platform, {BuildInfo? buildInfo, File? applicationBinary}) async {
+    platformRequested = platform;
+    applicationBinaryRequested = applicationBinary;
+    return applicationPackage;
+  }
+}
+
+class _FakeApplicationPackage extends Fake implements ApplicationPackage {}