blob: 4f28df3576e8800b544cc8fd403c2e5cdfc6ba99 [file] [log] [blame]
// Copyright 2018 The Chromium 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 'dart:async';
import 'dart:typed_data';
import 'package:file/file.dart';
import 'package:file/local.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:meta/meta.dart';
import 'package:flutter_goldens_client/client.dart';
export 'package:flutter_goldens_client/client.dart';
/// 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.
Future<void> main(FutureOr<void> testMain()) async {
goldenFileComparator = await FlutterGoldenFileComparator.fromDefaultComparator();
await testMain();
}
/// A golden file comparator specific to the `flutter/flutter` repository.
///
/// Within the https://github.com/flutter/flutter repository, it's important
/// not to check-in binaries in order to keep the size of the repository to a
/// minimum. To satisfy this requirement, this comparator retrieves the golden
/// files from a sibling repository, `flutter/goldens`.
///
/// This comparator will locally clone the `flutter/goldens` repository into
/// the `$FLUTTER_ROOT/bin/cache/pkg/goldens` folder, then perform the comparison against
/// the files therein.
class FlutterGoldenFileComparator implements GoldenFileComparator {
/// Creates a [FlutterGoldenFileComparator] that will resolve golden file
/// URIs relative to the specified [basedir].
///
/// The [fs] parameter exists for testing purposes only.
@visibleForTesting
FlutterGoldenFileComparator(
this.basedir, {
this.fs = const LocalFileSystem(),
});
/// The directory to which golden file URIs will be resolved in [compare] and [update].
final Uri basedir;
/// The file system used to perform file access.
@visibleForTesting
final FileSystem fs;
/// Creates a new [FlutterGoldenFileComparator] that mirrors the relative
/// path resolution of the default [goldenFileComparator].
///
/// By the time the future completes, the clone of the `flutter/goldens`
/// repository is guaranteed to be ready use.
///
/// The [goldens] and [defaultComparator] parameters are visible for testing
/// purposes only.
static Future<FlutterGoldenFileComparator> fromDefaultComparator({
GoldensClient goldens,
LocalFileComparator defaultComparator,
}) async {
defaultComparator ??= goldenFileComparator;
// Prepare the goldens repo.
goldens ??= GoldensClient();
await goldens.prepare();
// Calculate the appropriate basedir for the current test context.
final FileSystem fs = goldens.fs;
final Directory testDirectory = fs.directory(defaultComparator.basedir);
final String testDirectoryRelativePath = fs.path.relative(testDirectory.path, from: goldens.flutterRoot.path);
return FlutterGoldenFileComparator(goldens.repositoryRoot.childDirectory(testDirectoryRelativePath).uri);
}
@override
Future<bool> compare(Uint8List imageBytes, Uri golden) async {
final File goldenFile = _getGoldenFile(golden);
if (!goldenFile.existsSync()) {
throw TestFailure('Could not be compared against non-existent file: "$golden"');
}
final List<int> goldenBytes = await goldenFile.readAsBytes();
// TODO(tvolkert): Improve the intelligence of this comparison.
if (goldenBytes.length != imageBytes.length) {
return false;
}
for (int i = 0; i < goldenBytes.length; i++) {
if (goldenBytes[i] != imageBytes[i]) {
return false;
}
}
return true;
}
@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);
}
File _getGoldenFile(Uri uri) {
return fs.directory(basedir).childFile(fs.file(uri).path);
}
}