| // Copyright 2013 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 'dart:io'; |
| |
| import 'package:image/image.dart'; |
| import 'package:path/path.dart' as p; |
| |
| import 'environment.dart'; |
| import 'goldens.dart'; |
| |
| /// Compares a screenshot taken through a test with it's golden. |
| /// |
| /// Used by Flutter Web Engine unit tests and the integration tests. |
| /// |
| /// Returns the results of the tests as `String`. When tests passes the result |
| /// is simply `OK`, however when they fail it contains a detailed explanation |
| /// on which files are compared, their absolute locations and an HTML page |
| /// that the developer can see the comparison. |
| String compareImage( |
| Image screenshot, |
| bool doUpdateScreenshotGoldens, |
| String filename, |
| PixelComparison pixelComparison, |
| double maxDiffRateFailure, { |
| String goldensDirectory = '', |
| bool write = false, |
| }) { |
| final Environment environment = Environment(); |
| if (goldensDirectory.isEmpty) { |
| goldensDirectory = p.join( |
| environment.webUiGoldensRepositoryDirectory.path, |
| 'engine', |
| 'web', |
| ); |
| } |
| // Bail out fast if golden doesn't exist, and user doesn't want to create it. |
| final File file = File(p.join( |
| goldensDirectory, |
| filename, |
| )); |
| if (!file.existsSync() && !write) { |
| return ''' |
| Golden file $filename does not exist. |
| |
| To automatically create this file call matchGoldenFile('$filename', write: true). |
| '''; |
| } |
| if (write) { |
| // Don't even bother with the comparison, just write and return |
| print('Updating screenshot golden: $file'); |
| file.writeAsBytesSync(encodePng(screenshot), flush: true); |
| if (doUpdateScreenshotGoldens) { |
| // Do not fail tests when bulk-updating screenshot goldens. |
| return 'OK'; |
| } else { |
| return 'Golden file $filename was updated. You can remove "write: true" ' |
| 'in the call to matchGoldenFile.'; |
| } |
| } |
| |
| final Image golden = decodeNamedImage(file.readAsBytesSync(), filename)!; |
| |
| // Compare screenshots. |
| final ImageDiff diff = ImageDiff( |
| golden: golden, |
| other: screenshot, |
| pixelComparison: pixelComparison, |
| ); |
| |
| if (diff.rate > 0) { |
| final String testResultsPath = environment.webUiTestResultsDirectory.path; |
| Directory(testResultsPath).createSync(recursive: true); |
| final String basename = p.basenameWithoutExtension(file.path); |
| |
| final File actualFile = |
| File(p.join(testResultsPath, '$basename.actual.png')); |
| actualFile.writeAsBytesSync(encodePng(screenshot), flush: true); |
| |
| final File diffFile = File(p.join(testResultsPath, '$basename.diff.png')); |
| diffFile.writeAsBytesSync(encodePng(diff.diff), flush: true); |
| |
| final File expectedFile = |
| File(p.join(testResultsPath, '$basename.expected.png')); |
| file.copySync(expectedFile.path); |
| |
| final File reportFile = |
| File(p.join(testResultsPath, '$basename.report.html')); |
| reportFile.writeAsStringSync(''' |
| Golden file $filename did not match the image generated by the test. |
| |
| <table> |
| <tr> |
| <th>Expected</th> |
| <th>Diff</th> |
| <th>Actual</th> |
| </tr> |
| <tr> |
| <td> |
| <img src="$basename.expected.png"> |
| </td> |
| <td> |
| <img src="$basename.diff.png"> |
| </td> |
| <td> |
| <img src="$basename.actual.png"> |
| </td> |
| </tr> |
| </table> |
| '''); |
| |
| final StringBuffer message = StringBuffer(); |
| message.writeln( |
| 'Golden file $filename did not match the image generated by the test.'); |
| message.writeln(getPrintableDiffFilesInfo(diff.rate, maxDiffRateFailure)); |
| message.writeln('You can view the test report in your browser by opening:'); |
| |
| final String localReportPath = '$testResultsPath/$basename.report.html'; |
| message.writeln(localReportPath); |
| |
| message.writeln( |
| 'To update the golden file call matchGoldenFile(\'$filename\', write: ' |
| 'true).'); |
| message.writeln('Golden file: ${expectedFile.path}'); |
| message.writeln('Actual file: ${actualFile.path}'); |
| |
| if (diff.rate < maxDiffRateFailure) { |
| // Issue a warning but do not fail the test. |
| print('WARNING:'); |
| print(message); |
| return 'OK'; |
| } else { |
| // Fail test |
| return '$message'; |
| } |
| } |
| return 'OK'; |
| } |