Made build portable

dependencies/fluent_ui-3.12.0/test/dropdown_button_test.dart

@@ -0,0 +1,21 @@
+import 'package:fluent_ui/fluent_ui.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'app_test.dart';
+
+void main() {
+  testWidgets('DropdownButton leading is shown correctly', (tester) async {
+    await tester.pumpWidget(wrapApp(
+      child: DropDownButton(
+        items: [
+          MenuFlyoutItem(text: const Text('one'), onPressed: () {}),
+          MenuFlyoutItem(text: const Text('two'), onPressed: () {}),
+        ],
+        leading: const Icon(FluentIcons.number),
+        title: const Text('Numbers'),
+      ),
+    ));
+
+    expect(find.byIcon(FluentIcons.number), findsOneWidget);
+  });
+}