flutter/packages/flutter_test/test/finders_test.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/rendering.dart';
import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  group('text', () {
    testWidgets('finds Text widgets', (WidgetTester tester) async {
      await tester.pumpWidget(_boilerplate(
        const Text('test'),
      ));
      expect(find.text('test'), findsOneWidget);
    });

    testWidgets('finds Text.rich widgets', (WidgetTester tester) async {
      await tester.pumpWidget(_boilerplate(
        const Text.rich(
          TextSpan(text: 't', children: <TextSpan>[
            TextSpan(text: 'e'),
            TextSpan(text: 'st'),
          ],
        ),
      )));

      expect(find.text('test'), findsOneWidget);
    });
  });

  group('semantics', () {
    testWidgets('Throws StateError if semantics are not enabled', (WidgetTester tester) async {
      expect(() => find.bySemanticsLabel('Add'), throwsStateError);
    }, semanticsEnabled: false);

    testWidgets('finds Semantically labeled widgets', (WidgetTester tester) async {
      final SemanticsHandle semanticsHandle = tester.ensureSemantics();
      await tester.pumpWidget(_boilerplate(
        Semantics(
          label: 'Add',
          button: true,
          child: const FlatButton(
            child: Text('+'),
            onPressed: null,
          ),
        ),
      ));
      expect(find.bySemanticsLabel('Add'), findsOneWidget);
      semanticsHandle.dispose();
    });

    testWidgets('finds Semantically labeled widgets by RegExp', (WidgetTester tester) async {
      final SemanticsHandle semanticsHandle = tester.ensureSemantics();
      await tester.pumpWidget(_boilerplate(
        Semantics(
          container: true,
          child: Row(children: const <Widget>[
            Text('Hello'),
            Text('World'),
          ]),
        ),
      ));
      expect(find.bySemanticsLabel('Hello'), findsNothing);
      expect(find.bySemanticsLabel(RegExp(r'^Hello')), findsOneWidget);
      semanticsHandle.dispose();
    });

    testWidgets('finds Semantically labeled widgets without explicit Semantics', (WidgetTester tester) async {
      final SemanticsHandle semanticsHandle = tester.ensureSemantics();
      await tester.pumpWidget(_boilerplate(
        const SimpleCustomSemanticsWidget('Foo')
      ));
      expect(find.bySemanticsLabel('Foo'), findsOneWidget);
      semanticsHandle.dispose();
    });
  });

  group('hitTestable', () {
    testWidgets('excludes non-hit-testable widgets', (WidgetTester tester) async {
      await tester.pumpWidget(
        _boilerplate(IndexedStack(
          sizing: StackFit.expand,
          children: <Widget>[
            GestureDetector(
              key: const ValueKey<int>(0),
              behavior: HitTestBehavior.opaque,
              onTap: () { },
              child: const SizedBox.expand(),
            ),
            GestureDetector(
              key: const ValueKey<int>(1),
              behavior: HitTestBehavior.opaque,
              onTap: () { },
              child: const SizedBox.expand(),
            ),
          ],
        )),
      );
      expect(find.byType(GestureDetector), findsNWidgets(2));
      final Finder hitTestable = find.byType(GestureDetector).hitTestable(at: Alignment.center);
      expect(hitTestable, findsOneWidget);
      expect(tester.widget(hitTestable).key, const ValueKey<int>(0));
    });
  });

  testWidgets('ChainedFinders chain properly', (WidgetTester tester) async {
    final GlobalKey key1 = GlobalKey();
    await tester.pumpWidget(
      _boilerplate(Column(
        children: <Widget>[
          Container(
            key: key1,
            child: const Text('1'),
          ),
          Container(
            child: const Text('2'),
          ),
        ],
      )),
    );

    // Get the text back. By correctly chaining the descendant finder's
    // candidates, it should find 1 instead of 2. If the _LastFinder wasn't
    // correctly chained after the descendant's candidates, the last element
    // with a Text widget would have been 2.
    final Text text = find.descendant(
      of: find.byKey(key1),
      matching: find.byType(Text),
    ).last.evaluate().single.widget as Text;

    expect(text.data, '1');
  });
}

Widget _boilerplate(Widget child) {
  return Directionality(
    textDirection: TextDirection.ltr,
    child: child,
  );
}

class SimpleCustomSemanticsWidget extends LeafRenderObjectWidget {
  const SimpleCustomSemanticsWidget(this.label);

  final String label;

  @override
  RenderObject createRenderObject(BuildContext context) => SimpleCustomSemanticsRenderObject(label);
}

class SimpleCustomSemanticsRenderObject extends RenderBox {
  SimpleCustomSemanticsRenderObject(this.label);

  final String label;

  @override
  bool get sizedByParent => true;

  @override
  void describeSemanticsConfiguration(SemanticsConfiguration config) {
    super.describeSemanticsConfiguration(config);
    config..label = label..textDirection = TextDirection.ltr;
  }
}