import 'package:flutter/services.dart'; import 'package:flutter_test/flutter_test.dart'; void main() { TestWidgetsFlutterBinding.ensureInitialized(); const MethodChannel channel = MethodChannel('flutter_callkit_incoming'); final messenger = TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger; setUp(() { messenger.setMockMethodCallHandler(channel, (methodCall) async => '42'); }); tearDown(() { messenger.setMockMethodCallHandler(channel, null); }); }