packages/flutter/test/widgets/sliver_persistent_header_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/src/rendering/sliver_persistent_header.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('_SliverScrollingPersistentHeader should update stretchConfiguration', (
    WidgetTester tester,
  ) async {
    for (final stretchTriggerOffset in <double>[10.0, 20.0]) {
      await tester.pumpWidget(
        MaterialApp(
          home: CustomScrollView(
            slivers: <Widget>[
              SliverPersistentHeader(
                delegate: TestDelegate(
                  stretchConfiguration: OverScrollHeaderStretchConfiguration(
                    stretchTriggerOffset: stretchTriggerOffset,
                  ),
                ),
              ),
            ],
          ),
        ),
      );
    }

    expect(
      tester.allWidgets.where(
        (Widget w) => w.runtimeType.toString() == '_SliverScrollingPersistentHeader',
      ),
      isNotEmpty,
    );

    final RenderSliverScrollingPersistentHeader render = tester.allRenderObjects
        .whereType<RenderSliverScrollingPersistentHeader>()
        .first;
    expect(render.stretchConfiguration?.stretchTriggerOffset, 20);
  });

  testWidgets('_SliverPinnedPersistentHeader should update stretchConfiguration', (
    WidgetTester tester,
  ) async {
    for (final stretchTriggerOffset in <double>[10.0, 20.0]) {
      await tester.pumpWidget(
        MaterialApp(
          home: CustomScrollView(
            slivers: <Widget>[
              SliverPersistentHeader(
                pinned: true,
                delegate: TestDelegate(
                  stretchConfiguration: OverScrollHeaderStretchConfiguration(
                    stretchTriggerOffset: stretchTriggerOffset,
                  ),
                ),
              ),
            ],
          ),
        ),
      );
    }

    expect(
      tester.allWidgets.where(
        (Widget w) => w.runtimeType.toString() == '_SliverPinnedPersistentHeader',
      ),
      isNotEmpty,
    );

    final RenderSliverPinnedPersistentHeader render = tester.allRenderObjects
        .whereType<RenderSliverPinnedPersistentHeader>()
        .first;
    expect(render.stretchConfiguration?.stretchTriggerOffset, 20);
  });

  testWidgets('_SliverPinnedPersistentHeader should update showOnScreenConfiguration', (
    WidgetTester tester,
  ) async {
    for (final maxShowOnScreenExtent in <double>[1000, 2000]) {
      await tester.pumpWidget(
        MaterialApp(
          home: CustomScrollView(
            slivers: <Widget>[
              SliverPersistentHeader(
                pinned: true,
                delegate: TestDelegate(
                  showOnScreenConfiguration: PersistentHeaderShowOnScreenConfiguration(
                    maxShowOnScreenExtent: maxShowOnScreenExtent,
                  ),
                ),
              ),
            ],
          ),
        ),
      );
    }

    expect(
      tester.allWidgets.where(
        (Widget w) => w.runtimeType.toString() == '_SliverPinnedPersistentHeader',
      ),
      isNotEmpty,
    );

    final RenderSliverPinnedPersistentHeader render = tester.allRenderObjects
        .whereType<RenderSliverPinnedPersistentHeader>()
        .first;
    expect(render.showOnScreenConfiguration?.maxShowOnScreenExtent, 2000);
  });
}

class TestDelegate extends SliverPersistentHeaderDelegate {
  TestDelegate({this.stretchConfiguration, this.showOnScreenConfiguration});

  @override
  double get maxExtent => 200.0;

  @override
  double get minExtent => 200.0;

  @override
  Widget build(BuildContext context, double shrinkOffset, bool overlapsContent) {
    return Container(height: maxExtent);
  }

  @override
  bool shouldRebuild(TestDelegate oldDelegate) => false;

  @override
  final OverScrollHeaderStretchConfiguration? stretchConfiguration;
  @override
  final PersistentHeaderShowOnScreenConfiguration? showOnScreenConfiguration;
}