gen_l10n.dart tool testing (#44856)

* Add tests to gen_l10n.dart tool

* Separate out LocalizationsGenerator class to improve testability of code

* Add testing dependencies to dev/tools

* Integrate dev/tools testing to flutter CI

* Restructure dev/tools folder for testing

* Fix license headers

dev/bots/test.dart

@@ -423,6 +423,7 @@ Future<void> _runFrameworkTests() async {
     await _pubRunTest(path.join(flutterRoot, 'dev', 'bots'), tableData: bigqueryApi?.tabledata);
     await _pubRunTest(path.join(flutterRoot, 'dev', 'devicelab'), tableData: bigqueryApi?.tabledata);
     await _pubRunTest(path.join(flutterRoot, 'dev', 'snippets'), tableData: bigqueryApi?.tabledata);
+    await _pubRunTest(path.join(flutterRoot, 'dev', 'tools'), tableData: bigqueryApi?.tabledata);
     await _runFlutterTest(path.join(flutterRoot, 'dev', 'integration_tests', 'android_semantics_testing'), tableData: bigqueryApi?.tabledata);
     await _runFlutterTest(path.join(flutterRoot, 'dev', 'manual_tests'), tableData: bigqueryApi?.tabledata);
     await _runFlutterTest(path.join(flutterRoot, 'dev', 'tools', 'vitool'), tableData: bigqueryApi?.tabledata);

dev/tools/localization/bin/gen_l10n.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.
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:args/args.dart' as argslib;
+import 'package:file/local.dart' as local;
+import 'package:path/path.dart' as path;
+
+import '../gen_l10n.dart';
+import '../localizations_utils.dart';
+
+Future<void> main(List<String> arguments) async {
+  final argslib.ArgParser parser = argslib.ArgParser();
+  parser.addFlag(
+    'help',
+    defaultsTo: false,
+    negatable: false,
+    help: 'Print this help message.',
+  );
+  parser.addOption(
+    'arb-dir',
+    defaultsTo: path.join('lib', 'l10n'),
+    help: 'The directory where all localization files should reside. For '
+      'example, the template and translated arb files should be located here. '
+      'Also, the generated output messages Dart files for each locale and the '
+      'generated localizations classes will be created here.',
+  );
+  parser.addOption(
+    'template-arb-file',
+    defaultsTo: 'app_en.arb',
+    help: 'The template arb file that will be used as the basis for '
+      'generating the Dart localization and messages files.',
+  );
+  parser.addOption(
+    'output-localization-file',
+    defaultsTo: 'app_localizations.dart',
+    help: 'The filename for the output localization and localizations '
+      'delegate classes.',
+  );
+  parser.addOption(
+    'output-class',
+    defaultsTo: 'AppLocalizations',
+    help: 'The Dart class name to use for the output localization and '
+      'localizations delegate classes.',
+  );
+
+  final argslib.ArgResults results = parser.parse(arguments);
+  if (results['help'] == true) {
+    print(parser.usage);
+    exit(0);
+  }
+
+  final String arbPathString = results['arb-dir'];
+  final String outputFileString = results['output-localization-file'];
+  final String templateArbFileName = results['template-arb-file'];
+  final String classNameString = results['output-class'];
+
+  const local.LocalFileSystem fs = local.LocalFileSystem();
+  final LocalizationsGenerator localizationsGenerator = LocalizationsGenerator(fs);
+  try {
+    localizationsGenerator
+      ..initialize(
+        l10nDirectoryPath: arbPathString,
+        templateArbFileName: templateArbFileName,
+        outputFileString: outputFileString,
+        classNameString: classNameString,
+      )
+      ..parseArbFiles()
+      ..generateClassMethods()
+      ..generateOutputFile();
+  } on FileSystemException catch (e) {
+    exitWithError(e.message);
+  } on FormatException catch (e) {
+    exitWithError(e.message);
+  } on L10nException catch (e) {
+    exitWithError(e.message);
+  }
+
+  final ProcessResult pubGetResult = await Process.run('flutter', <String>['pub', 'get']);
+  if (pubGetResult.exitCode != 0) {
+    stderr.write(pubGetResult.stderr);
+    exit(1);
+  }
+
+  final ProcessResult generateFromArbResult = await Process.run('flutter', <String>[
+    'pub',
+    'run',
+    'intl_translation:generate_from_arb',
+    '--output-dir=${localizationsGenerator.l10nDirectory.path}',
+    '--no-use-deferred-loading',
+    localizationsGenerator.outputFile.path,
+    ...localizationsGenerator.arbFilenames,
+  ]);
+  if (generateFromArbResult.exitCode != 0) {
+    stderr.write(generateFromArbResult.stderr);
+    exit(1);
+  }
+}

dev/tools/pubspec.yaml

@@ -29,12 +29,44 @@ dependencies:
   typed_data: 1.1.6 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
 
 dev_dependencies:
+  test: 1.9.4
   test_api: 0.2.11
   mockito: 4.1.1
 
+  analyzer: 0.38.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   boolean_selector: 1.0.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  coverage: 0.13.3+1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  csslib: 0.16.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  front_end: 0.1.27 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  glob: 1.2.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  html: 0.14.0+3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  http_multi_server: 2.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  io: 0.3.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  js: 0.6.1+1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  kernel: 0.3.27 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  logging: 0.11.3+2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   matcher: 0.12.6 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  mime: 0.9.6+3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  multi_server_socket: 1.0.2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  node_interop: 1.0.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  node_io: 1.0.1+2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  node_preamble: 1.4.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  package_config: 1.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  package_resolver: 1.0.10 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  pool: 1.4.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  pub_semver: 1.4.2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  shelf: 0.7.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  shelf_packages_handler: 1.0.4 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  shelf_static: 0.2.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  shelf_web_socket: 0.2.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  source_map_stack_trace: 1.1.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  source_maps: 0.10.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   stack_trace: 1.9.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   stream_channel: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  test_core: 0.2.15 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  vm_service: 1.2.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  watcher: 0.9.7+13 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  web_socket_channel: 1.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  yaml: 2.2.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
 
-# PUBSPEC CHECKSUM: a9e9
+# PUBSPEC CHECKSUM: 3590

dev/tools/test/common.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.
+
+import 'dart:io';
+
+import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
+import 'package:test/test.dart' as test_package show TypeMatcher;
+
+export 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
+
+// Defines a 'package:test' shim.
+// TODO(ianh): Remove this file once https://github.com/dart-lang/matcher/issues/98 is fixed
+
+/// A matcher that compares the type of the actual value to the type argument T.
+Matcher isInstanceOf<T>() => test_package.TypeMatcher<T>();
+
+void tryToDelete(Directory directory) {
+  // This should not be necessary, but it turns out that
+  // on Windows it's common for deletions to fail due to
+  // bogus (we think) "access denied" errors.
+  try {
+    directory.deleteSync(recursive: true);
+  } on FileSystemException catch (error) {
+    print('Failed to delete ${directory.path}: $error');
+  }
+}

examples/stocks/lib/i18n/regenerate.md

@@ -15,7 +15,7 @@ for more info.
 `messages_all.dart`, and `stock_strings.dart` with the following command:
 
 ```dart
-dart ${FLUTTER_PATH}/dev/tools/localization/gen_l10n.dart --arb-dir=lib/i18n \
+dart ${FLUTTER_PATH}/dev/tools/localization/bin/gen_l10n.dart --arb-dir=lib/i18n \
     --template-arb-file=stocks_en_US.arb --output-localization-file=stock_strings.dart \
     --output-class=StockStrings
 ```