chore(vertexai): follow up changes for LiveModel

packages/firebase_vertexai/firebase_vertexai/example/lib/pages/bidi_page.dart

@@ -59,7 +59,7 @@ class _BidiPageState extends State<BidiPage> {
     super.initState();
 
     final config = LiveGenerationConfig(
-      speechConfig: SpeechConfig(voice: Voice.Fenrir),
+      speechConfig: SpeechConfig(voice: Voice.fenrir),
       responseModalities: [
         ResponseModalities.audio,
       ],

packages/firebase_vertexai/firebase_vertexai/lib/src/error.dart

@@ -138,7 +138,15 @@ final class LiveWebSocketClosedException implements Exception {
   final String message;
 
   @override
-  String toString() => message;
+  String toString() {
+    if (message.contains('DEADLINE_EXCEEDED')) {
+      return 'The current live session has expired. Please start a new session.';
+    } else if (message.contains('RESOURCE_EXHAUSTED')) {
+      return 'You have exceeded the maximum number of concurrent sessions. '
+          'Please close other sessions and try again later.';
+    }
+    return message;
+  }
 }
 
 /// Parse the error json object.
@@ -150,7 +158,8 @@ VertexAIException parseError(Object jsonObject) {
     } =>
       InvalidApiKey(message),
     {'message': UnsupportedUserLocation._message} => UnsupportedUserLocation(),
-    {'message': final String message} when message.contains('quota') =>
+    {'message': final String message}
+        when message.toLowerCase().contains('quota') =>
       QuotaExceeded(message),
     {
       'message': final String _,

packages/firebase_vertexai/firebase_vertexai/lib/src/live_api.dart

@@ -17,20 +17,20 @@ import 'error.dart';
 
 /// The available voice options for speech synthesis.
 enum Voice {
-  // ignore: public_member_api_docs, constant_identifier_names
-  Aoede('Aoede'),
+  // ignore: public_member_api_docs
+  aoede('Aoede'),
 
-  // ignore: public_member_api_docs, constant_identifier_names
-  Charon('Charon'),
+  // ignore: public_member_api_docs
+  charon('Charon'),
 
-  // ignore: public_member_api_docs, constant_identifier_names
-  Fenrir('Fenrir'),
+  // ignore: public_member_api_docs
+  fenrir('Fenrir'),
 
-  // ignore: public_member_api_docs, constant_identifier_names
-  Kore('Kore'),
+  // ignore: public_member_api_docs
+  kore('Kore'),
 
-  // ignore: public_member_api_docs, constant_identifier_names
-  Puck('Puck');
+  // ignore: public_member_api_docs
+  puck('Puck');
 
   const Voice(this._jsonString);
   final String _jsonString;

packages/firebase_vertexai/firebase_vertexai/lib/src/live_session.dart

@@ -131,7 +131,7 @@ class LiveSession {
   void _checkWsStatus() {
     if (_ws.closeCode != null) {
       var message =
-          'WebSocket status: Closed, closeCode: ${_ws.closeCode}, closeReason: ${_ws.closeReason}';
+          'WebSocket Closed, closeCode: ${_ws.closeCode}, closeReason: ${_ws.closeReason}';
 
       throw LiveWebSocketClosedException(message);
     }

packages/firebase_vertexai/firebase_vertexai/test/error_test.dart

@@ -0,0 +1,165 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'package:firebase_vertexai/src/error.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('VertexAI Exceptions', () {
+    test('VertexAIException toString', () {
+      final exception = VertexAIException('Test message');
+      expect(exception.toString(), 'VertexAIException: Test message');
+    });
+
+    test('InvalidApiKey toString', () {
+      final exception = InvalidApiKey('Invalid API key provided.');
+      expect(exception.toString(), 'Invalid API key provided.');
+    });
+
+    test('UnsupportedUserLocation message', () {
+      final exception = UnsupportedUserLocation();
+      expect(
+          exception.message, 'User location is not supported for the API use.');
+    });
+
+    test('ServiceApiNotEnabled message', () {
+      final exception = ServiceApiNotEnabled('projects/test-project');
+      expect(
+          exception.message,
+          'The Vertex AI in Firebase SDK requires the Vertex AI in Firebase API '
+          '(`firebasevertexai.googleapis.com`) to be enabled in your Firebase project. Enable this API '
+          'by visiting the Firebase Console at '
+          'https://console.firebase.google.com/project/test-project/genai '
+          'and clicking "Get started". If you enabled this API recently, wait a few minutes for the '
+          'action to propagate to our systems and then retry.');
+    });
+
+    test('QuotaExceeded toString', () {
+      final exception = QuotaExceeded('Quota for this API has been exceeded.');
+      expect(exception.toString(), 'Quota for this API has been exceeded.');
+    });
+
+    test('ServerException toString', () {
+      final exception = ServerException('Server error occurred.');
+      expect(exception.toString(), 'Server error occurred.');
+    });
+
+    test('VertexAISdkException toString', () {
+      final exception = VertexAISdkException('SDK failed to parse response.');
+      expect(
+          exception.toString(),
+          'SDK failed to parse response.\n'
+          'This indicates a problem with the Vertex AI in Firebase SDK. '
+          'Try updating to the latest version '
+          '(https://pub.dev/packages/firebase_vertexai/versions), '
+          'or file an issue at '
+          'https://github.com/firebase/flutterfire/issues.');
+    });
+
+    test('ImagenImagesBlockedException toString', () {
+      final exception =
+          ImagenImagesBlockedException('All images were blocked.');
+      expect(exception.toString(), 'All images were blocked.');
+    });
+
+    test('LiveWebSocketClosedException toString - DEADLINE_EXCEEDED', () {
+      final exception = LiveWebSocketClosedException(
+          'DEADLINE_EXCEEDED: Connection timed out.');
+      expect(exception.toString(),
+          'The current live session has expired. Please start a new session.');
+    });
+
+    test('LiveWebSocketClosedException toString - RESOURCE_EXHAUSTED', () {
+      final exception = LiveWebSocketClosedException(
+          'RESOURCE_EXHAUSTED: Too many connections.');
+      expect(
+          exception.toString(),
+          'You have exceeded the maximum number of concurrent sessions. '
+          'Please close other sessions and try again later.');
+    });
+
+    test('LiveWebSocketClosedException toString - Other', () {
+      final exception =
+          LiveWebSocketClosedException('WebSocket connection closed.');
+      expect(exception.toString(), 'WebSocket connection closed.');
+    });
+
+    group('parseError', () {
+      test('parses API_KEY_INVALID', () {
+        final json = {
+          'message': 'Invalid API key',
+          'details': [
+            {'reason': 'API_KEY_INVALID'}
+          ]
+        };
+        final exception = parseError(json);
+        expect(exception, isInstanceOf<InvalidApiKey>());
+        expect(exception.message, 'Invalid API key');
+      });
+
+      test('parses UNSUPPORTED_USER_LOCATION', () {
+        final json = {
+          'message': 'User location is not supported for the API use.'
+        };
+        final exception = parseError(json);
+        expect(exception, isInstanceOf<UnsupportedUserLocation>());
+      });
+
+      test('parses QUOTA_EXCEEDED', () {
+        final json = {'message': 'Quota exceeded: Limit reached.'};
+        final exception = parseError(json);
+        expect(exception, isInstanceOf<QuotaExceeded>());
+        expect(exception.message, 'Quota exceeded: Limit reached.');
+      });
+
+      test('parses SERVICE_API_NOT_ENABLED', () {
+        final json = {
+          'message': 'API not enabled',
+          'status': 'PERMISSION_DENIED',
+          'details': [
+            {
+              'metadata': {
+                'service': 'firebasevertexai.googleapis.com',
+                'consumer': 'projects/my-project-id',
+              }
+            }
+          ]
+        };
+        final exception = parseError(json);
+        expect(exception, isInstanceOf<ServiceApiNotEnabled>());
+        expect(
+            (exception as ServiceApiNotEnabled).message,
+            'The Vertex AI in Firebase SDK requires the Vertex AI in Firebase API '
+            '(`firebasevertexai.googleapis.com`) to be enabled in your Firebase project. Enable this API '
+            'by visiting the Firebase Console at '
+            'https://console.firebase.google.com/project/my-project-id/genai '
+            'and clicking "Get started". If you enabled this API recently, wait a few minutes for the '
+            'action to propagate to our systems and then retry.');
+      });
+
+      test('parses SERVER_ERROR', () {
+        final json = {'message': 'Internal server error.'};
+        final exception = parseError(json);
+        expect(exception, isInstanceOf<ServerException>());
+        expect(exception.message, 'Internal server error.');
+      });
+
+      test('parses UNHANDLED_FORMAT', () {
+        final json = {'unexpected': 'format'};
+        expect(() => parseError(json),
+            throwsA(isInstanceOf<VertexAISdkException>()));
+      });
+    });
+  });
+}

packages/firebase_vertexai/firebase_vertexai/test/live_test.dart

@@ -21,15 +21,15 @@ import 'package:flutter_test/flutter_test.dart';
 void main() {
   group('LiveAPI Tests', () {
     test('Voices enum toJson() returns correct value', () {
-      expect(Voice.Aoede.toJson(), 'Aoede');
-      expect(Voice.Charon.toJson(), 'Charon');
-      expect(Voice.Fenrir.toJson(), 'Fenrir');
-      expect(Voice.Kore.toJson(), 'Kore');
-      expect(Voice.Puck.toJson(), 'Puck');
+      expect(Voice.aoede.toJson(), 'Aoede');
+      expect(Voice.charon.toJson(), 'Charon');
+      expect(Voice.fenrir.toJson(), 'Fenrir');
+      expect(Voice.kore.toJson(), 'Kore');
+      expect(Voice.puck.toJson(), 'Puck');
     });
 
     test('SpeechConfig toJson() returns correct JSON', () {
-      final speechConfigWithVoice = SpeechConfig(voice: Voice.Aoede);
+      final speechConfigWithVoice = SpeechConfig(voice: Voice.aoede);
       expect(speechConfigWithVoice.toJson(), {
         'voice_config': {
           'prebuilt_voice_config': {'voice_name': 'Aoede'}
@@ -49,7 +49,7 @@ void main() {
 
     test('LiveGenerationConfig toJson() returns correct JSON', () {
       final liveGenerationConfig = LiveGenerationConfig(
-        speechConfig: SpeechConfig(voice: Voice.Charon),
+        speechConfig: SpeechConfig(voice: Voice.charon),
         responseModalities: [ResponseModalities.text, ResponseModalities.audio],
         candidateCount: 2,
         maxOutputTokens: 100,