flutter_goldens.dart 20.6 KB
Newer Older
Ian Hickson's avatar
Ian Hickson committed
1
// Copyright 2014 The Flutter Authors. All rights reserved.
2 3
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
4

5 6 7 8 9 10 11 12 13
import 'dart:async' show FutureOr;
import 'dart:io' as io show OSError, SocketException;

import 'package:file/file.dart';
import 'package:file/local.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_goldens_client/skia_client.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:platform/platform.dart';
14

15
export 'package:flutter_goldens_client/skia_client.dart';
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545

// If you are here trying to figure out how to use golden files in the Flutter
// repo itself, consider reading this wiki page:
// https://github.com/flutter/flutter/wiki/Writing-a-golden-file-test-for-package%3Aflutter

const String _kFlutterRootKey = 'FLUTTER_ROOT';

/// Main method that can be used in a `flutter_test_config.dart` file to set
/// [goldenFileComparator] to an instance of [FlutterGoldenFileComparator] that
/// works for the current test. _Which_ FlutterGoldenFileComparator is
/// instantiated is based on the current testing environment.
///
/// When set, the `namePrefix` is prepended to the names of all gold images.
Future<void> testExecutable(FutureOr<void> Function() testMain, {String? namePrefix}) async {
  const Platform platform = LocalPlatform();
  if (FlutterPostSubmitFileComparator.isAvailableForEnvironment(platform)) {
    goldenFileComparator = await FlutterPostSubmitFileComparator.fromDefaultComparator(platform, namePrefix: namePrefix);
  } else if (FlutterPreSubmitFileComparator.isAvailableForEnvironment(platform)) {
    goldenFileComparator = await FlutterPreSubmitFileComparator.fromDefaultComparator(platform, namePrefix: namePrefix);
  } else if (FlutterSkippingFileComparator.isAvailableForEnvironment(platform)) {
    goldenFileComparator = FlutterSkippingFileComparator.fromDefaultComparator(
      'Golden file testing is not executed on Cirrus, or LUCI environments outside of flutter/flutter.',
        namePrefix: namePrefix
    );
  } else {
    goldenFileComparator = await FlutterLocalFileComparator.fromDefaultComparator(platform);
  }

  await testMain();
}

/// Abstract base class golden file comparator specific to the `flutter/flutter`
/// repository.
///
/// Golden file testing for the `flutter/flutter` repository is handled by three
/// different [FlutterGoldenFileComparator]s, depending on the current testing
/// environment.
///
///   * The [FlutterPostSubmitFileComparator] is utilized during post-submit
///     testing, after a pull request has landed on the master branch. This
///     comparator uses the [SkiaGoldClient] and the `goldctl` tool to upload
///     tests to the [Flutter Gold dashboard](https://flutter-gold.skia.org).
///     Flutter Gold manages the master golden files for the `flutter/flutter`
///     repository.
///
///   * The [FlutterPreSubmitFileComparator] is utilized in pre-submit testing,
///     before a pull request lands on the master branch. This
///     comparator uses the [SkiaGoldClient] to execute tryjobs, allowing
///     contributors to view and check in visual differences before landing the
///     change.
///
///   * The [FlutterLocalFileComparator] is used for local development testing.
///     This comparator will use the [SkiaGoldClient] to request baseline images
///     from [Flutter Gold](https://flutter-gold.skia.org) and manually compare
///     pixels. If a difference is detected, this comparator will
///     generate failure output illustrating the found difference. If a baseline
///     is not found for a given test image, it will consider it a new test and
///     output the new image for verification.
///
///  The [FlutterSkippingFileComparator] is utilized to skip tests outside
///  of the appropriate environments described above. Currently, some Luci
///  environments do not execute golden file testing, and as such do not require
///  a comparator. This comparator is also used when an internet connection is
///  unavailable.
abstract class FlutterGoldenFileComparator extends GoldenFileComparator {
  /// Creates a [FlutterGoldenFileComparator] that will resolve golden file
  /// URIs relative to the specified [basedir], and retrieve golden baselines
  /// using the [skiaClient]. The [basedir] is used for writing and accessing
  /// information and files for interacting with the [skiaClient]. When testing
  /// locally, the [basedir] will also contain any diffs from failed tests, or
  /// goldens generated from newly introduced tests.
  ///
  /// The [fs] and [platform] parameters are useful in tests, where the default
  /// file system and platform can be replaced by mock instances.
  @visibleForTesting
  FlutterGoldenFileComparator(
    this.basedir,
    this.skiaClient, {
    this.fs = const LocalFileSystem(),
    this.platform = const LocalPlatform(),
    this.namePrefix,
  });

  /// The directory to which golden file URIs will be resolved in [compare] and
  /// [update], cannot be null.
  final Uri basedir;

  /// A client for uploading image tests and making baseline requests to the
  /// Flutter Gold Dashboard, cannot be null.
  final SkiaGoldClient skiaClient;

  /// The file system used to perform file access.
  @visibleForTesting
  final FileSystem fs;

  /// A wrapper for the [dart:io.Platform] API.
  @visibleForTesting
  final Platform platform;

  /// The prefix that is added to all golden names.
  final String? namePrefix;

  @override
  Future<void> update(Uri golden, Uint8List imageBytes) async {
    final File goldenFile = getGoldenFile(golden);
    await goldenFile.parent.create(recursive: true);
    await goldenFile.writeAsBytes(imageBytes, flush: true);
  }

  @override
  Uri getTestUri(Uri key, int? version) => key;

  /// Calculate the appropriate basedir for the current test context.
  ///
  /// The optional [suffix] argument is used by the
  /// [FlutterPostSubmitFileComparator] and the [FlutterPreSubmitFileComparator].
  /// These [FlutterGoldenFileComparators] randomize their base directories to
  /// maintain thread safety while using the `goldctl` tool.
  @protected
  @visibleForTesting
  static Directory getBaseDirectory(
    LocalFileComparator defaultComparator,
    Platform platform, {
    String? suffix,
  }) {
    const FileSystem fs = LocalFileSystem();
    final Directory flutterRoot = fs.directory(platform.environment[_kFlutterRootKey]);
    Directory comparisonRoot;

    if (suffix != null) {
      comparisonRoot = fs.systemTempDirectory.createTempSync(suffix);
    } else {
      comparisonRoot = flutterRoot.childDirectory(
        fs.path.join(
          'bin',
          'cache',
          'pkg',
          'skia_goldens',
        )
      );
    }

    final Directory testDirectory = fs.directory(defaultComparator.basedir);
    final String testDirectoryRelativePath = fs.path.relative(
      testDirectory.path,
      from: flutterRoot.path,
    );
    return comparisonRoot.childDirectory(testDirectoryRelativePath);
  }

  /// Returns the golden [File] identified by the given [Uri].
  @protected
  File getGoldenFile(Uri uri) {
    final File goldenFile = fs.directory(basedir).childFile(fs.file(uri).path);
    return goldenFile;
  }

  /// Prepends the golden URL with the library name that encloses the current
  /// test.
  Uri _addPrefix(Uri golden) {
    // Ensure the Uri ends in .png as the SkiaClient expects
    assert(
      golden.toString().split('.').last == 'png',
      'Golden files in the Flutter framework must end with the file extension '
      '.png.'
    );
    return Uri.parse(<String>[
      if (namePrefix != null)
        namePrefix!,
      basedir.pathSegments[basedir.pathSegments.length - 2],
      golden.toString(),
    ].join('.'));
  }
}

/// A [FlutterGoldenFileComparator] for testing golden images with Skia Gold in
/// post-submit.
///
/// For testing across all platforms, the [SkiaGoldClient] is used to upload
/// images for framework-related golden tests and process results.
///
/// See also:
///
///  * [GoldenFileComparator], the abstract class that
///    [FlutterGoldenFileComparator] implements.
///  * [FlutterPreSubmitFileComparator], another
///    [FlutterGoldenFileComparator] that tests golden images before changes are
///    merged into the master branch.
///  * [FlutterLocalFileComparator], another
///    [FlutterGoldenFileComparator] that tests golden images locally on your
///    current machine.
class FlutterPostSubmitFileComparator extends FlutterGoldenFileComparator {
  /// Creates a [FlutterPostSubmitFileComparator] that will test golden file
  /// images against Skia Gold.
  ///
  /// The [fs] and [platform] parameters are useful in tests, where the default
  /// file system and platform can be replaced by mock instances.
  FlutterPostSubmitFileComparator(
    super.basedir,
    super.skiaClient, {
    super.fs,
    super.platform,
    super.namePrefix,
  });

  /// Creates a new [FlutterPostSubmitFileComparator] that mirrors the relative
  /// path resolution of the default [goldenFileComparator].
  ///
  /// The [goldens] and [defaultComparator] parameters are visible for testing
  /// purposes only.
  static Future<FlutterPostSubmitFileComparator> fromDefaultComparator(
    final Platform platform, {
    SkiaGoldClient? goldens,
    LocalFileComparator? defaultComparator,
    String? namePrefix,
  }) async {

    defaultComparator ??= goldenFileComparator as LocalFileComparator;
    final Directory baseDirectory = FlutterGoldenFileComparator.getBaseDirectory(
      defaultComparator,
      platform,
      suffix: 'flutter_goldens_postsubmit.',
    );
    baseDirectory.createSync(recursive: true);

    goldens ??= SkiaGoldClient(baseDirectory);
    await goldens.auth();
    return FlutterPostSubmitFileComparator(baseDirectory.uri, goldens, namePrefix: namePrefix);
  }

  @override
  Future<bool> compare(Uint8List imageBytes, Uri golden) async {
    await skiaClient.imgtestInit();
    golden = _addPrefix(golden);
    await update(golden, imageBytes);
    final File goldenFile = getGoldenFile(golden);

    return skiaClient.imgtestAdd(golden.path, goldenFile);
  }

  /// Decides based on the current environment if goldens tests should be
  /// executed through Skia Gold.
  static bool isAvailableForEnvironment(Platform platform) {
    final bool luciPostSubmit = platform.environment.containsKey('SWARMING_TASK_ID')
      && platform.environment.containsKey('GOLDCTL')
      // Luci tryjob environments contain this value to inform the [FlutterPreSubmitComparator].
      && !platform.environment.containsKey('GOLD_TRYJOB');

    return luciPostSubmit;
  }
}

/// A [FlutterGoldenFileComparator] for testing golden images before changes are
/// merged into the master branch. The comparator executes tryjobs using the
/// [SkiaGoldClient].
///
/// See also:
///
///  * [GoldenFileComparator], the abstract class that
///    [FlutterGoldenFileComparator] implements.
///  * [FlutterPostSubmitFileComparator], another
///    [FlutterGoldenFileComparator] that uploads tests to the Skia Gold
///    dashboard in post-submit.
///  * [FlutterLocalFileComparator], another
///    [FlutterGoldenFileComparator] that tests golden images locally on your
///    current machine.
class FlutterPreSubmitFileComparator extends FlutterGoldenFileComparator {
  /// Creates a [FlutterPreSubmitFileComparator] that will test golden file
  /// images against baselines requested from Flutter Gold.
  ///
  /// The [fs] and [platform] parameters are useful in tests, where the default
  /// file system and platform can be replaced by mock instances.
  FlutterPreSubmitFileComparator(
    super.basedir,
    super.skiaClient, {
    super.fs,
    super.platform,
    super.namePrefix,
  });

  /// Creates a new [FlutterPreSubmitFileComparator] that mirrors the
  /// relative path resolution of the default [goldenFileComparator].
  ///
  /// The [goldens] and [defaultComparator] parameters are visible for testing
  /// purposes only.
  static Future<FlutterGoldenFileComparator> fromDefaultComparator(
    final Platform platform, {
    SkiaGoldClient? goldens,
    LocalFileComparator? defaultComparator,
    Directory? testBasedir,
    String? namePrefix,
  }) async {

    defaultComparator ??= goldenFileComparator as LocalFileComparator;
    final Directory baseDirectory = testBasedir ?? FlutterGoldenFileComparator.getBaseDirectory(
      defaultComparator,
      platform,
      suffix: 'flutter_goldens_presubmit.',
    );

    if (!baseDirectory.existsSync()) {
      baseDirectory.createSync(recursive: true);
    }

    goldens ??= SkiaGoldClient(baseDirectory);

    await goldens.auth();
    return FlutterPreSubmitFileComparator(
      baseDirectory.uri,
      goldens, platform: platform,
      namePrefix: namePrefix,
    );
  }

  @override
  Future<bool> compare(Uint8List imageBytes, Uri golden) async {
    await skiaClient.tryjobInit();
    golden = _addPrefix(golden);
    await update(golden, imageBytes);
    final File goldenFile = getGoldenFile(golden);

    await skiaClient.tryjobAdd(golden.path, goldenFile);

    // This will always return true since golden file test failures are managed
    // in pre-submit checks by the flutter-gold status check.
    return true;
  }

  /// Decides based on the current environment if goldens tests should be
  /// executed as pre-submit tests with Skia Gold.
  static bool isAvailableForEnvironment(Platform platform) {
    final bool luciPreSubmit = platform.environment.containsKey('SWARMING_TASK_ID')
      && platform.environment.containsKey('GOLDCTL')
      && platform.environment.containsKey('GOLD_TRYJOB');
    return luciPreSubmit;
  }
}

/// A [FlutterGoldenFileComparator] for testing conditions that do not execute
/// golden file tests.
///
/// Currently, this comparator is used on Cirrus, or in Luci environments when executing tests
/// outside of the flutter/flutter repository.
///
/// See also:
///
///  * [FlutterPostSubmitFileComparator], another [FlutterGoldenFileComparator]
///    that tests golden images through Skia Gold.
///  * [FlutterPreSubmitFileComparator], another
///    [FlutterGoldenFileComparator] that tests golden images before changes are
///    merged into the master branch.
///  * [FlutterLocalFileComparator], another
///    [FlutterGoldenFileComparator] that tests golden images locally on your
///    current machine.
class FlutterSkippingFileComparator extends FlutterGoldenFileComparator {
  /// Creates a [FlutterSkippingFileComparator] that will skip tests that
  /// are not in the right environment for golden file testing.
  FlutterSkippingFileComparator(
    super.basedir,
    super.skiaClient,
    this.reason, {
    super.namePrefix,
  });

  /// Describes the reason for using the [FlutterSkippingFileComparator].
  ///
  /// Cannot be null.
  final String reason;

  /// Creates a new [FlutterSkippingFileComparator] that mirrors the
  /// relative path resolution of the default [goldenFileComparator].
  static FlutterSkippingFileComparator fromDefaultComparator(
    String reason, {
    LocalFileComparator? defaultComparator,
    String? namePrefix,
  }) {
    defaultComparator ??= goldenFileComparator as LocalFileComparator;
    const FileSystem fs = LocalFileSystem();
    final Uri basedir = defaultComparator.basedir;
    final SkiaGoldClient skiaClient = SkiaGoldClient(fs.directory(basedir));
    return FlutterSkippingFileComparator(basedir, skiaClient, reason, namePrefix: namePrefix);
  }

  @override
  Future<bool> compare(Uint8List imageBytes, Uri golden) async {
    // Ideally we would use markTestSkipped here but in some situations,
    // comparators are called outside of tests.
    // See also: https://github.com/flutter/flutter/issues/91285
    // ignore: avoid_print
    print('Skipping "$golden" test: $reason');
    return true;
  }

  @override
  Future<void> update(Uri golden, Uint8List imageBytes) async {}

  /// Decides, based on the current environment, if this comparator should be
  /// used.
  ///
  /// If we are in a CI environment, LUCI or Cirrus, but are not using the other
  /// comparators, we skip.
  static bool isAvailableForEnvironment(Platform platform) {
    return platform.environment.containsKey('SWARMING_TASK_ID')
      // Some builds are still being run on Cirrus, we should skip these.
      || platform.environment.containsKey('CIRRUS_CI');
  }
}

/// A [FlutterGoldenFileComparator] for testing golden images locally on your
/// current machine.
///
/// This comparator utilizes the [SkiaGoldClient] to request baseline images for
/// the given device under test for comparison. This comparator is initialized
/// when conditions for all other [FlutterGoldenFileComparators] have not been
/// met, see the `isAvailableForEnvironment` method for each one listed below.
///
/// The [FlutterLocalFileComparator] is intended to run on local machines and
/// serve as a smoke test during development. As such, it will not be able to
/// detect unintended changes on environments other than the currently executing
/// machine, until they are tested using the [FlutterPreSubmitFileComparator].
///
/// See also:
///
///  * [GoldenFileComparator], the abstract class that
///    [FlutterGoldenFileComparator] implements.
///  * [FlutterPostSubmitFileComparator], another
///    [FlutterGoldenFileComparator] that uploads tests to the Skia Gold
///    dashboard.
///  * [FlutterPreSubmitFileComparator], another
///    [FlutterGoldenFileComparator] that tests golden images before changes are
///    merged into the master branch.
///  * [FlutterSkippingFileComparator], another
///    [FlutterGoldenFileComparator] that controls post-submit testing
///    conditions that do not execute golden file tests.
class FlutterLocalFileComparator extends FlutterGoldenFileComparator with LocalComparisonOutput {
  /// Creates a [FlutterLocalFileComparator] that will test golden file
  /// images against baselines requested from Flutter Gold.
  ///
  /// The [fs] and [platform] parameters are useful in tests, where the default
  /// file system and platform can be replaced by mock instances.
  FlutterLocalFileComparator(
    super.basedir,
    super.skiaClient, {
    super.fs,
    super.platform,
  });

  /// Creates a new [FlutterLocalFileComparator] that mirrors the
  /// relative path resolution of the default [goldenFileComparator].
  ///
  /// The [goldens], [defaultComparator], and [baseDirectory] parameters are
  /// visible for testing purposes only.
  static Future<FlutterGoldenFileComparator> fromDefaultComparator(
    final Platform platform, {
    SkiaGoldClient? goldens,
    LocalFileComparator? defaultComparator,
    Directory? baseDirectory,
  }) async {
    defaultComparator ??= goldenFileComparator as LocalFileComparator;
    baseDirectory ??= FlutterGoldenFileComparator.getBaseDirectory(
      defaultComparator,
      platform,
    );

    if(!baseDirectory.existsSync()) {
      baseDirectory.createSync(recursive: true);
    }

    goldens ??= SkiaGoldClient(baseDirectory);
    try {
      // Check if we can reach Gold.
      await goldens.getExpectationForTest('');
    } on io.OSError catch (_) {
      return FlutterSkippingFileComparator(
        baseDirectory.uri,
        goldens,
        'OSError occurred, could not reach Gold. '
          'Switching to FlutterSkippingGoldenFileComparator.',
      );
    } on io.SocketException catch (_) {
      return FlutterSkippingFileComparator(
        baseDirectory.uri,
        goldens,
        'SocketException occurred, could not reach Gold. '
          'Switching to FlutterSkippingGoldenFileComparator.',
      );
    }

    return FlutterLocalFileComparator(baseDirectory.uri, goldens);
  }

  @override
  Future<bool> compare(Uint8List imageBytes, Uri golden) async {
    golden = _addPrefix(golden);
    final String testName = skiaClient.cleanTestName(golden.path);
    late String? testExpectation;
    testExpectation = await skiaClient.getExpectationForTest(testName);

    if (testExpectation == null || testExpectation.isEmpty) {
      // There is no baseline for this test.
      // Ideally we would use markTestSkipped here but in some situations,
      // comparators are called outside of tests.
      // See also: https://github.com/flutter/flutter/issues/91285
      // ignore: avoid_print
      print(
        'No expectations provided by Skia Gold for test: $golden. '
        'This may be a new test. If this is an unexpected result, check '
        'https://flutter-gold.skia.org.\n'
        'Validate image output found at $basedir'
      );
      update(golden, imageBytes);
      return true;
    }

    ComparisonResult result;
    final List<int> goldenBytes = await skiaClient.getImageBytes(testExpectation);

    result = await GoldenFileComparator.compareLists(
      imageBytes,
      goldenBytes,
    );

    if (result.passed) {
      return true;
    }

    final String error = await generateFailureOutput(result, golden, basedir);
    throw FlutterError(error);
  }
}