examples/api/test/widgets/draggable_scrollable_sheet/draggable_scrollable_sheet.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/draggable_scrollable_sheet/draggable_scrollable_sheet.0.dart' as example;
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('Test DraggableScrollableSheet initial state', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.DraggableScrollableSheetExampleApp(),
    );

    final Finder sheetFinder = find.byType(DraggableScrollableSheet);

    // Verify that DraggableScrollableSheet is initially present
    expect(sheetFinder, findsOneWidget);

    // Verify that DraggableScrollableSheet is shown initially at 50% height
    final DraggableScrollableSheet draggableSheet = tester.widget(sheetFinder);
    expect(draggableSheet.initialChildSize, 0.5);
  });

  testWidgets('Test DraggableScrollableSheet drag behavior on mobile platforms', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.DraggableScrollableSheetExampleApp(),
    );

    // Verify that ListView is visible
    final Finder listViewFinder = find.byType(ListView);
    expect(listViewFinder, findsOneWidget);

    // Get the initial size of the ListView
    final Size listViewInitialSize = tester.getSize(listViewFinder);

    // Drag the sheet from anywhere inside the sheet to change the sheet position
    await tester.drag(listViewFinder, const Offset(0.0, -100.0));
    await tester.pump();

    // Verify that the ListView is expanded
    final Size listViewCurrentSize = tester.getSize(listViewFinder);
    expect(listViewCurrentSize.height, greaterThan(listViewInitialSize.height));
  }, variant: TargetPlatformVariant.mobile());

  testWidgets('Test DraggableScrollableSheet drag behavior on desktop platforms', (WidgetTester tester) async {
    await tester.pumpWidget(
      const example.DraggableScrollableSheetExampleApp(),
    );

    // Verify that Grabber is visible
    final Finder grabberFinder = find.byType(example.Grabber);
    expect(grabberFinder, findsOneWidget);

    // Drag the Grabber to change the sheet position
    await tester.drag(grabberFinder, const Offset(0.0, -100.0));
    await tester.pump();

    // Verify that the DraggableScrollableSheet's initialChildSize is updated
    final DraggableScrollableSheet draggableSheet = tester.widget(find.byType(DraggableScrollableSheet));
    expect(draggableSheet.initialChildSize, isNot(0.5));
  }, variant: TargetPlatformVariant.desktop());
}