flutter-go/packages/flutter_web/test/widgets/gesture_disambiguation_test.dart

// Copyright 2017 The Chromium 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_web_test/flutter_web_test.dart';
import 'package:flutter_web/widgets.dart';
import 'package:flutter_web/gestures.dart';

void main() {
  testWidgets('onTap detection with canceled pointer and a drag listener',
      (WidgetTester tester) async {
    int detector1TapCount = 0;
    int detector2TapCount = 0;

    final Widget widget = GestureDetector(
        child: Column(
      mainAxisAlignment: MainAxisAlignment.start,
      children: <Widget>[
        GestureDetector(
          onTap: () {
            detector1TapCount += 1;
          },
          behavior: HitTestBehavior.opaque,
          child: const SizedBox(width: 200.0, height: 200.0),
        ),
        GestureDetector(
            onTap: () {
              detector2TapCount += 1;
            },
            behavior: HitTestBehavior.opaque,
            child: const SizedBox(width: 200.0, height: 200.0))
      ],
    ));

    await tester.pumpWidget(widget);

    // The following pointer event sequence was causing the issue described
    // in https://github.com/flutter/flutter/issues/12470 by triggering 2 tap
    // events on the second detector.
    final TestGesture gesture1 =
        await tester.startGesture(const Offset(400.0, 10.0));
    final TestGesture gesture2 =
        await tester.startGesture(const Offset(400.0, 210.0));
    await gesture1.up();
    await gesture2.cancel();
    final TestGesture gesture3 =
        await tester.startGesture(const Offset(400.0, 250.0));
    await gesture3.up();

    expect(detector1TapCount, 1);
    expect(detector2TapCount, 1);
  });
}