dev/automated_tests/flutter_test/flutter_gold_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.

// See also packages/flutter_goldens/test/flutter_goldens_test.dart

import 'dart:typed_data';

import 'package:file/file.dart';
import 'package:file/memory.dart';
import 'package:flutter_goldens/flutter_goldens.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:platform/platform.dart';

// 1x1 colored pixel
const List<int> _kFailPngBytes = <int>[
  137, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0,
  13, 73, 72, 68, 82, 0, 0, 0, 1, 0, 0, 0, 1, 8, 6, 0, 0, 0, 31, 21, 196, 137,
  0, 0, 0, 13, 73, 68, 65, 84, 120, 1, 99, 249, 207, 240, 255, 63, 0, 7, 18, 3,
  2, 164, 147, 160, 197, 0, 0, 0, 0, 73, 69, 78, 68, 174, 66, 96, 130,
];

void main() {
  final MemoryFileSystem fs = MemoryFileSystem();
  final Directory basedir = fs.directory('flutter/test/library/')
    ..createSync(recursive: true);
  final FakeSkiaGoldClient fakeSkiaClient = FakeSkiaGoldClient()
    ..expectationForTestValues['flutter.new_golden_test.1'] = '';
  final FlutterLocalFileComparator comparator = FlutterLocalFileComparator(
    basedir.uri,
    fakeSkiaClient,
    fs: fs,
    platform: FakePlatform(
      environment: <String, String>{'FLUTTER_ROOT': '/flutter'},
      operatingSystem: 'macos'
    ),
  );

  test('Local passes non-existent baseline for new test, null expectation', () async {
    expect(
      await comparator.compare(
        Uint8List.fromList(_kFailPngBytes),
        Uri.parse('flutter.new_golden_test.1.png'),
      ),
      isTrue,
    );
  });

  test('Local passes non-existent baseline for new test, empty expectation', () async {
    expect(
      await comparator.compare(
        Uint8List.fromList(_kFailPngBytes),
        Uri.parse('flutter.new_golden_test.2.png'),
      ),
      isTrue,
    );
  });
}

// See also packages/flutter_goldens/test/flutter_goldens_test.dart
class FakeSkiaGoldClient extends Fake implements SkiaGoldClient {
  Map<String, String> expectationForTestValues = <String, String>{};
  Object? getExpectationForTestThrowable;
  @override
  Future<String> getExpectationForTest(String testName) async {
    if (getExpectationForTestThrowable != null) {
      throw getExpectationForTestThrowable!;
    }
    return expectationForTestValues[testName] ?? '';
  }

  Map<String, List<int>> imageBytesValues = <String, List<int>>{};
  @override
  Future<List<int>> getImageBytes(String imageHash) async => imageBytesValues[imageHash]!;

  Map<String, String> cleanTestNameValues = <String, String>{};
  @override
  String cleanTestName(String fileName) => cleanTestNameValues[fileName] ?? '';
}