examples/api/test/cupertino/nav_bar/cupertino_sliver_nav_bar.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/cupertino.dart';
import 'package:flutter_api_samples/cupertino/nav_bar/cupertino_sliver_nav_bar.0.dart' as example;
import 'package:flutter_test/flutter_test.dart';

const Offset dragUp = Offset(0.0, -150.0);

void main() {
  testWidgets('Collapse and expand CupertinoSliverNavigationBar changes title position', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.SliverNavBarApp(),
    );

    // Large title is visible and at lower position.
    expect(tester.getBottomLeft(find.text('Contacts').first).dy, 88.0);
    await tester.fling(find.text('Drag me up'), dragUp, 500.0);
    await tester.pumpAndSettle();

    // Large title is hidden and at higher position.
    expect(tester.getBottomLeft(find.text('Contacts').first).dy, 36.0 + 8.0); // Static part + _kNavBarBottomPadding.
  });

  testWidgets('Middle widget is visible in both collapsed and expanded states', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.SliverNavBarApp(),
    );

    // Navigate to a page that has both middle and large titles.
    final Finder nextButton = find.text('Go to Next Page');
    expect(nextButton, findsOneWidget);
    await tester.tap(nextButton);
    await tester.pumpAndSettle();

    // Both middle and large titles are visible.
    expect(tester.getBottomLeft(find.text('Contacts Group').first).dy, 30.5);
    expect(tester.getBottomLeft(find.text('Family').first).dy, 88.0);

    await tester.fling(find.text('Drag me up'), dragUp, 500.0);
    await tester.pumpAndSettle();

    // Large title is hidden and middle title is visible.
    expect(tester.getBottomLeft(find.text('Contacts Group').first).dy, 30.5);
    expect(tester.getBottomLeft(find.text('Family').first).dy, 36.0 + 8.0); // Static part + _kNavBarBottomPadding.
  });

  testWidgets('CupertinoSliverNavigationBar with previous route has back button', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.SliverNavBarApp(),
    );

    // Navigate to a page that has back button
    final Finder nextButton = find.text('Go to Next Page');
    expect(nextButton, findsOneWidget);
    await tester.tap(nextButton);
    await tester.pumpAndSettle();
    expect(nextButton, findsNothing);

    // Go back to the previous page.
    final Finder backButton = find.byType(CupertinoButton);
    expect(backButton, findsOneWidget);
    await tester.tap(backButton);
    await tester.pumpAndSettle();
    expect(nextButton, findsOneWidget);
  });
}