title: How to find off-screen ListView child in widget tests?
body: <p>When displaying multiple children in a ListView, if a child is off-screen it can't be found by a widget test. Here's a full example:</p>
  
  <p>main.dart</p>
  
  <pre><code>import 'package:flutter/material.dart';
  
  void main() =&gt; runApp(App());
  
  class App extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(home: Scaffold(body: Test()));
    }
  }
  
  class Test extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return ListView(
        children: &lt;Widget&gt;[
          Container(
            height: 600,
            color: Colors.red,
          ),
          Text("Find me!"),
        ],
      );
    }
  }
  </code></pre>
  
  <p>main_test.dart</p>
  
  <pre><code>import 'package:flutter_app/main.dart';
  import 'package:flutter_test/flutter_test.dart';
  
  void main() {
    testWidgets("Find text", (WidgetTester tester) async {
      final testableWidget = App();
  
      await tester.pumpWidget(testableWidget);
  
      expect(find.text("Find me!"), findsOneWidget);
    });
  }
  </code></pre>
  
  <p>This test fails, however if I change the height of the <code>Container</code> in main.dart to <code>599</code> it works. </p>
  
  <p>Anyone know why this happens? Is it a bug? Is there a way around it?</p>