add core/api tests

Signed-off-by: Sahil Kumar <[email protected]>

packages/stream_chat/test/src/mocks.dart

@@ -1,6 +1,14 @@
 import 'package:dio/dio.dart';
 import 'package:logging/logging.dart';
 import 'package:mocktail/mocktail.dart';
+import 'package:stream_chat/src/core/api/attachment_file_uploader.dart';
+import 'package:stream_chat/src/core/api/channel_api.dart';
+import 'package:stream_chat/src/core/api/device_api.dart';
+import 'package:stream_chat/src/core/api/general_api.dart';
+import 'package:stream_chat/src/core/api/guest_api.dart';
+import 'package:stream_chat/src/core/api/message_api.dart';
+import 'package:stream_chat/src/core/api/moderation_api.dart';
+import 'package:stream_chat/src/core/api/user_api.dart';
 import 'package:stream_chat/src/core/http/connection_id_manager.dart';
 import 'package:stream_chat/src/core/http/stream_http_client.dart';
 import 'package:stream_chat/src/core/http/token_manager.dart';
@@ -32,3 +40,20 @@ class MockHttpClient extends Mock implements StreamHttpClient {}
 class MockTokenManager extends Mock implements TokenManager {}
 
 class MockConnectionIdManager extends Mock implements ConnectionIdManager {}
+
+class MockUserApi extends Mock implements UserApi {}
+
+class MockGuestApi extends Mock implements GuestApi {}
+
+class MockMessageApi extends Mock implements MessageApi {}
+
+class MockChannelApi extends Mock implements ChannelApi {}
+
+class MockDeviceApi extends Mock implements DeviceApi {}
+
+class MockModerationApi extends Mock implements ModerationApi {}
+
+class MockGeneralApi extends Mock implements GeneralApi {}
+
+class MockAttachmentFileUploader extends Mock
+    implements AttachmentFileUploader {}