test that flutter_rust_bridge works

flutter_app/integration_test/simple_test.dart

@@ -0,0 +1,13 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_app/main.dart';
+import 'package:flutter_app/src/rust/frb_generated.dart';
+import 'package:integration_test/integration_test.dart';
+
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+  setUpAll(() async => await RustLib.init());
+  testWidgets('Can call rust function', (WidgetTester tester) async {
+    await tester.pumpWidget(const MyApp());
+    expect(find.textContaining('Result: `Hello, Tom!`'), findsOneWidget);
+  });
+}