Flutter Driver scrolling through dropdown list - flutter

Question

I would like to scroll through a drop-down list as part of a flutter driver test, however I can't seem to figure out exactly how I would do this?
I've tried using a ValueKey, and have tried digging through the Flutter Inspector in Intellij as well, but have had no luck thus far.

Answer 1

I have tried find.byType(Scrollable); and it doesn't seem to work even after widgetTester.tap(). Turns out I need to wait for the screen to update with widgetTester.pumpAndSettle()
testWidgets("Test DropdownButton", (WidgetTester widgetTester) async {
await widgetTester.pumpWidget(MyApp())
final dropdownButtonFinder = find.byKey(const ValueKey('DropdownButton')); final dropdownItemFinder = find.widgetWithText(InkWell, 'Item 50'); // find.textContaining() doesn't seem to work
// Tap on the DropdownButton
await widgetTester.tap(dropdownButtonFinder);
await widgetTester.pumpAndSettle(const Duration(seconds: 2));
final dropdownListFinder = find.byType(Scrollable);
expect(dropdownListFinder, findsOneWidget); // Finds Scrollable from tapping DropDownButton
// Scroll until the item to be found appears.
await widgetTester.scrollUntilVisible(dropdownItemFinder, 500.0,
scrollable: dropdownListFinder);
await widgetTester.tap(dropdownItemFinder);
await widgetTester.pumpAndSettle(const Duration(seconds: 2));
// Verify that the item contains the correct text.
expect(find.textContaining('Item 50'), findsOneWidget);
});
Main code
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key? key, required this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<String> mockList() => List<String>.generate(100, (i) => 'Item $i');
String? dropdownValue;
#override
Widget build(BuildContext context) {
// debugPrint('${foo!}');
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
key: Key('Widget1'),
),
body: Center(
child: DropdownButton(
key: Key('DropdownButton'),
value: dropdownValue,
onChanged: (String? newValue) {
setState(() {
dropdownValue = newValue!;
});
},
items: mockList()
.map<DropdownMenuItem<String>>(
(String value) => DropdownMenuItem<String>(
value: value,
child: Text(value),
key: Key('item$value'),
),
)
.toList(),
)
);
}
}
Running the test