examples/api/test/widgets/page_view/page_view.0_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/material.dart';
import 'package:flutter_api_samples/widgets/page_view/page_view.0.dart' as example;
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('PageView swipe gestures on mobile platforms', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.PageViewExampleApp(),
    );

    // Verify that first page is shown initially.
    expect(find.text('First Page'), findsOneWidget);

    // Swipe to the left.
    await tester.fling(find.text('First Page'), const Offset(-300.0, 0.0), 3000);
    await tester.pumpAndSettle();
    // Verify that the second page is shown.
    expect(find.text('Second Page'), findsOneWidget);

    // Swipe back to the right.
    await tester.fling(find.text('Second Page'), const Offset(300.0, 0.0), 3000);
    await tester.pumpAndSettle();
    // Verify that first page is shown.
    expect(find.text('First Page'), findsOneWidget);
  }, variant: TargetPlatformVariant.mobile());

  testWidgets('PageView navigation using forward/backward buttons on desktop platforms', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.PageViewExampleApp(),
    );

    // Verify that first page is shown along with forward/backward buttons in page indicator.
    expect(find.text('First Page'), findsOneWidget);
    expect(find.byType(TabPageSelector), findsOneWidget);

    // Tap forward button on page indicator area.
    await tester.tap(find.byIcon(Icons.arrow_right_rounded));
    await tester.pumpAndSettle();
    // Verify that second page is shown.
    expect(find.text('Second Page'), findsOneWidget);

    // Verify that page indicator index is updated.
    final TabPageSelector pageIndicator = tester.widget<TabPageSelector>(find.byType(TabPageSelector));
    expect(pageIndicator.controller?.index, 1);

    // Verify that page view index is also updated with same index to page indicator.
    final PageView pageView = tester.widget<PageView>(find.byType(PageView));
    expect(pageView.controller.page, 1);

    // Tap backward button on page indicator area.
    await tester.tap(find.byIcon(Icons.arrow_left_rounded));
    await tester.pumpAndSettle();
    // Verify that first page is shown.
    expect(find.text('First Page'), findsOneWidget);

    // Tap backward button one more time.
    await tester.tap(find.byIcon(Icons.arrow_left_rounded));
    await tester.pumpAndSettle();
    // Verify that first page is still shown.
    expect(find.text('First Page'), findsOneWidget);
  }, variant: TargetPlatformVariant.desktop());
}