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import 'dart:typed_data';
import 'package:flutter/services.dart';
import 'package:image/image.dart' as img;

/// GIFアセットを単一フレームPNGへ変換して返すAssetBundleラッパー。
class TestGifToPngAssetBundle extends CachingAssetBundle {
  TestGifToPngAssetBundle(this._parent);

  final AssetBundle _parent;

  @override
  Future<ByteData> load(String key) async {
    // GIF以外はそのまま親に委譲
    if (!key.toLowerCase().endsWith('.gif')) {
      return _parent.load(key);
    }

    // GIFの最初のフレームを指定して変換
    final gifData = await _parent.load(key);
    final frame = img.decodeGif(gifData.buffer.asUint8List(), frame: 3);

    if (frame == null) {
      return gifData;
    }

    final pngBytes = Uint8List.fromList(img.encodePng(frame));
    return ByteData.sublistView(pngBytes);
  }
}

import 'dart:typed_data';
import 'package:flutter/services.dart';
import 'package:image/image.dart' as img;

/// GIFアセットを単一フレームPNGへ変換して返すAssetBundleラッパー。
class TestGifToPngAssetBundle extends CachingAssetBundle {
  TestGifToPngAssetBundle(this._parent);

  final AssetBundle _parent;

  @override
  Future<ByteData> load(String key) async {
    // GIF以外はそのまま親に委譲
    if (!key.toLowerCase().endsWith('.gif')) {
      return _parent.load(key);
    }

    // GIFの最初のフレームを指定して変換
    final gifData = await _parent.load(key);
    final frame = img.decodeGif(gifData.buffer.asUint8List(), frame: 3);

    if (frame == null) {
      return gifData;
    }

    final pngBytes = Uint8List.fromList(img.encodePng(frame));
    return ByteData.sublistView(pngBytes);
  }
}

import 'package:alchemist/alchemist.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:golden_test_sample/main.dart';

import 'support/alchemist/golden_test_device_scenario.dart';
import 'support/test_gif_to_png_asset_bundle.dart';

void main() {
  group('MyApp Golden Test', () {
    Widget buildMyApp() {
      return const MainApp();
    }

    final device = Device.phonePortrait;

    goldenTest(
      'Default',
      fileName: 'my_app_default',
      pumpBeforeTest: precacheImages,
      builder: () {
        final children = <Widget>[];

        children.add(
          GoldenTestDeviceScenario(
            name: device.name,
            device: device,
            builder: () => buildMyApp(),
          ),
        );

        return DefaultAssetBundle(
          bundle: TestGifToPngAssetBundle(rootBundle),
          child: GoldenTestGroup(children: children),
        );
      },
    );
  });
}

import 'package:alchemist/alchemist.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:golden_test_sample/main.dart';

import 'support/alchemist/golden_test_device_scenario.dart';
import 'support/test_gif_to_png_asset_bundle.dart';

void main() {
  group('MyApp Golden Test', () {
    Widget buildMyApp() {
      return const MainApp();
    }

    final device = Device.phonePortrait;

    goldenTest(
      'Default',
      fileName: 'my_app_default',
      pumpBeforeTest: precacheImages,
      builder: () {
        final children = <Widget>[];

        children.add(
          GoldenTestDeviceScenario(
            name: device.name,
            device: device,
            builder: () => buildMyApp(),
          ),
        );

        return DefaultAssetBundle(
          bundle: TestGifToPngAssetBundle(rootBundle),
          child: GoldenTestGroup(children: children),
        );
      },
    );
  });
}

Future<void> customPrecacheImages(WidgetTester tester) async {
  await tester.runAsync(() async {
    final images = <Future<void>>[];
    for (final element in find.byType(Image).evaluate()) {
      final widget = element.widget as Image;
      images.add(_precacheWithGifFrame(widget.image, element));
    }
    for (final element in find.byType(FadeInImage).evaluate()) {
      final widget = element.widget as FadeInImage;
      images.add(_precacheWithGifFrame(widget.image, element));
    }
    for (final element in find.byType(DecoratedBox).evaluate()) {
      final widget = element.widget as DecoratedBox;
      final decoration = widget.decoration;
      if (decoration is BoxDecoration && decoration.image != null) {
        images.add(_precacheWithGifFrame(decoration.image!.image, element));
      }
    }
    await Future.wait(images);
  });
  await tester.pumpAndSettle();
}

Future<void> _precacheWithGifFrame(
  ImageProvider<Object> provider,
  Element element,
) async {
  if (provider is AssetImage &&
      provider.assetName.toLowerCase().endsWith('.gif')) {
    final configuration = createLocalImageConfiguration(element);
    final key = await provider.obtainKey(configuration);
    final pngBytes = await _gifFrameToPng(key, frameIndex: 0);
    final memoryImage = MemoryImage(pngBytes, scale: key.scale);
    await precacheImage(memoryImage, element);
    return;
  }
  await precacheImage(provider, element);
}

Future<Uint8List> _gifFrameToPng(
  AssetBundleImageKey key, {
  required int frameIndex,
}) async {
  final bundle = key.bundle;
  final data = await bundle.load(key.name);
  final frame = img.decodeGif(data.buffer.asUint8List(), frame: frameIndex);
  if (frame == null) {
    throw StateError('フレームを取得できませんでした: ${key.name} (frame: $frameIndex)');
  }
  return Uint8List.fromList(img.encodePng(frame, singleFrame: true));
}

Future<void> customPrecacheImages(WidgetTester tester) async {
  await tester.runAsync(() async {
    final images = <Future<void>>[];
    for (final element in find.byType(Image).evaluate()) {
      final widget = element.widget as Image;
      images.add(_precacheWithGifFrame(widget.image, element));
    }
    for (final element in find.byType(FadeInImage).evaluate()) {
      final widget = element.widget as FadeInImage;
      images.add(_precacheWithGifFrame(widget.image, element));
    }
    for (final element in find.byType(DecoratedBox).evaluate()) {
      final widget = element.widget as DecoratedBox;
      final decoration = widget.decoration;
      if (decoration is BoxDecoration && decoration.image != null) {
        images.add(_precacheWithGifFrame(decoration.image!.image, element));
      }
    }
    await Future.wait(images);
  });
  await tester.pumpAndSettle();
}

Future<void> _precacheWithGifFrame(
  ImageProvider<Object> provider,
  Element element,
) async {
  if (provider is AssetImage &&
      provider.assetName.toLowerCase().endsWith('.gif')) {
    final configuration = createLocalImageConfiguration(element);
    final key = await provider.obtainKey(configuration);
    final pngBytes = await _gifFrameToPng(key, frameIndex: 0);
    final memoryImage = MemoryImage(pngBytes, scale: key.scale);
    await precacheImage(memoryImage, element);
    return;
  }
  await precacheImage(provider, element);
}

Future<Uint8List> _gifFrameToPng(
  AssetBundleImageKey key, {
  required int frameIndex,
}) async {
  final bundle = key.bundle;
  final data = await bundle.load(key.name);
  final frame = img.decodeGif(data.buffer.asUint8List(), frame: frameIndex);
  if (frame == null) {
    throw StateError('フレームを取得できませんでした: ${key.name} (frame: $frameIndex)');
  }
  return Uint8List.fromList(img.encodePng(frame, singleFrame: true));
}