overhaul tests

test/models/shared_chat_session_test.dart

@@ -0,0 +1,41 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:frosty/models/shared_chat_session.dart';
+
+import '../fixtures/api_responses.dart';
+
+void main() {
+  group('SharedChatSession', () {
+    test('fromJson deserializes all fields', () {
+      final session = SharedChatSession.fromJson(
+        (twitchSharedChatSessionResponse['data']! as List).first
+            as Map<String, dynamic>,
+      );
+
+      expect(session.sessionId, 'session_123');
+      expect(session.hostBroadcasterId, '12345');
+      expect(session.participants.length, 2);
+      expect(session.createdAt, '2024-01-01T00:00:00Z');
+      expect(session.updatedAt, '2024-01-01T01:00:00Z');
+    });
+  });
+
+  group('Participant', () {
+    test('fromJson deserializes broadcaster_id', () {
+      final participant = Participant.fromJson(const {
+        'broadcaster_id': '67890',
+      });
+
+      expect(participant.broadcasterId, '67890');
+    });
+
+    test('participants from shared chat session are correct', () {
+      final session = SharedChatSession.fromJson(
+        (twitchSharedChatSessionResponse['data']! as List).first
+            as Map<String, dynamic>,
+      );
+
+      expect(session.participants[0].broadcasterId, '12345');
+      expect(session.participants[1].broadcasterId, '67890');
+    });
+  });
+}