Catch StateError and output more useful error message when DDS fails to start (#72736)

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

diff --git a/packages/flutter_tools/test/general.shard/resident_runner_test.dart b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
index aaaab19..e0606a8 100644
--- a/packages/flutter_tools/test/general.shard/resident_runner_test.dart
+++ b/packages/flutter_tools/test/general.shard/resident_runner_test.dart
@@ -2683,6 +2683,7 @@
     when(mockDevice.getLogReader(app: anyNamed('app'))).thenReturn(mockLogReader);
     when(mockDevice.dds).thenReturn(mockDds);
     when(mockDds.startDartDevelopmentService(any, any, any, any)).thenThrow(FakeDartDevelopmentServiceException());
+    when(mockDds.uri).thenReturn(Uri.parse('http://localhost:1234'));
     when(mockDds.done).thenAnswer((_) => noopCompleter.future);
 
     final TestFlutterDevice flutterDevice = TestFlutterDevice(
@@ -2703,6 +2704,36 @@
     }) async => mockVMService,
   }));
 
+  testUsingContext('Failed DDS start outputs error message', () => testbed.run(() async {
+    // See https://github.com/flutter/flutter/issues/72385 for context.
+    fakeVmServiceHost = FakeVmServiceHost(requests: <VmServiceExpectation>[]);
+    final MockDevice mockDevice = MockDevice();
+    when(mockDevice.dds).thenReturn(DartDevelopmentService(logger: testLogger));
+    ddsLauncherCallback = (Uri uri, {bool enableAuthCodes, bool ipv6, Uri serviceUri}) {
+      throw FakeDartDevelopmentServiceException(message: 'No URI');
+    };
+    final TestFlutterDevice flutterDevice = TestFlutterDevice(
+      mockDevice,
+      observatoryUris: Stream<Uri>.value(testUri),
+    );
+    bool caught = false;
+    final Completer<void>done = Completer<void>();
+    runZonedGuarded(() {
+      flutterDevice.connect(allowExistingDdsInstance: true).then((_) => done.complete());
+    }, (Object e, StackTrace st) {
+      expect(e is StateError, true);
+      expect((e as StateError).message, contains('No URI'));
+      expect(testLogger.errorText, contains(
+        'DDS has failed to start and there is not an existing DDS instance',
+      ));
+      done.complete();
+      caught = true;
+    });
+    await done.future;
+    if (!caught) {
+      fail('Expected a StateError to be thrown.');
+    }
+  }));
 
   testUsingContext('nextPlatform moves through expected platforms', () {
     expect(nextPlatform('android', TestFeatureFlags()), 'iOS');
@@ -2726,11 +2757,14 @@
 class MockResidentCompiler extends Mock implements ResidentCompiler {}
 
 class FakeDartDevelopmentServiceException implements dds.DartDevelopmentServiceException {
+  FakeDartDevelopmentServiceException({this.message = defaultMessage});
+
   @override
   final int errorCode = dds.DartDevelopmentServiceException.existingDdsInstanceError;
 
   @override
-  final String message = 'A DDS instance is already connected at http://localhost:8181';
+  final String message;
+  static const String defaultMessage = 'A DDS instance is already connected at http://localhost:8181';
 }
 
 class TestFlutterDevice extends FlutterDevice {