[Gallery] Add Travis CI check that l10n command has been run for the gallery (#263)

* Add command to grind to verify that l10n command has ben run

Author: perclasson

gallery/README.md

@@ -65,7 +65,7 @@ for more details):
 flutter pub run grinder l10n
 ```
 
-To generate code segments (see separate [README](codeviewer_cli/README.md) for
+To generate code segments (see separate [README](gallery/tool/codeviewer_cli/README.md) for
 more details):
 ```
 flutter pub run grinder update-code-segments

gallery/gallery/tool/grind.dart

@@ -47,10 +47,32 @@ Future<void> generateLocalizations() async {
 @Task('Transform arb to xml for English')
 @Depends(generateLocalizations)
 Future<void> l10n() async {
-  final l10nPath = path.join(Directory.current.parent.path, 'l10n_cli');
-  await pubGet(directory: l10nPath);
+  final l10nPath =
+      path.join(Directory.current.path, 'tool', 'l10n_cli', 'main.dart');
+  Dart.run(l10nPath);
+}
+
+@Task('Verify xml localizations')
+Future<void> verifyL10n() async {
+  final l10nPath =
+      path.join(Directory.current.path, 'tool', 'l10n_cli', 'main.dart');
+
+  // Run the tool to transform arb to xml, and write the output to stdout.
+  final xmlOutput = Dart.run(l10nPath, arguments: ['--dry-run'], quiet: true);
+
+  // Read the original xml file.
+  final xmlPath =
+      path.join(Directory.current.path, 'lib', 'l10n', 'intl_en_US.xml');
+  final expectedXmlOutput = await File(xmlPath).readAsString();
 
-  Dart.run(path.join(l10nPath, 'bin', 'main.dart'));
+  if (xmlOutput.trim() != expectedXmlOutput.trim()) {
+    stderr.writeln(
+      'The contents of $xmlPath are different from that produced by '
+      'l10n_cli. Did you forget to run `flutter pub run grinder '
+      'l10n` after updating an .arb file?',
+    );
+    exit(1);
+  }
 }
 
 @Task('Update code segments')

gallery/gallery/tool/l10n_cli/README.md

@@ -0,0 +1,4 @@
+# l10n
+
+A command-line application that converts .arb files to .xml files for
+translation consumption.

gallery/l10n_cli/lib/l10n_cli.dart renamed to gallery/gallery/tool/l10n_cli/l10n_cli.dart

@@ -37,24 +37,29 @@ String _escapeXml(String xml) {
 }
 
 /// Processes the XML files.
-Future<void> englishArbsToXmls() async {
+Future<void> englishArbsToXmls({bool isDryRun = false}) async {
+  IOSink output =
+      isDryRun ? stdout : File('$_l10nDir/intl_en_US.xml').openWrite();
   await generateXmlFromArb(
     inputArb: File('$_l10nDir/intl_en_US.arb'),
-    outputXml: File('$_l10nDir/intl_en_US.xml'),
+    outputXml: output,
     xmlHeader: _intlHeader,
   );
+  await output.close();
 }
 
 @visibleForTesting
 Future<void> generateXmlFromArb({
   File inputArb,
-  File outputXml,
+  IOSink outputXml,
   String xmlHeader,
 }) async {
-  final Map<String, dynamic> bundle = jsonDecode(await inputArb.readAsString());
+  final Map<String, dynamic> bundle =
+      jsonDecode(await inputArb.readAsString()) as Map<String, dynamic>;
+
   String translationFor(String key) {
     assert(bundle[key] != null);
-    return _escapeXml(bundle[key]);
+    return _escapeXml(bundle[key] as String);
   }
 
   final xml = StringBuffer(xmlHeader);
@@ -70,9 +75,9 @@ Future<void> generateXmlFromArb({
 
     final resourceId = key.substring(1);
     final name = _escapeXml(resourceId);
-    final Map<String, dynamic> metaInfo = bundle[key];
+    final metaInfo = bundle[key] as Map<String, dynamic>;
     assert(metaInfo != null && metaInfo['description'] != null);
-    var description = _escapeXml(metaInfo['description']);
+    var description = _escapeXml(metaInfo['description'] as String);
 
     if (metaInfo.containsKey('plural')) {
       // Generate a plurals resource element formatted like this:
@@ -110,8 +115,8 @@ Future<void> generateXmlFromArb({
       // description's 'parameters' value, are replaced with printf positional
       // string arguments, like "%1$s".
       var translation = translationFor(resourceId);
-      assert(metaInfo['parameters'].trim().isNotEmpty);
-      final parameters = metaInfo['parameters']
+      assert((metaInfo['parameters'] as String).trim().isNotEmpty);
+      final parameters = (metaInfo['parameters'] as String)
           .split(',')
           .map<String>((s) => s.trim())
           .toList();
@@ -139,6 +144,5 @@ Future<void> generateXmlFromArb({
     }
   }
   xml.writeln('</resources>');
-
-  await outputXml.writeAsString(xml.toString());
+  outputXml.write(xml.toString());
 }

gallery/gallery/tool/l10n_cli/main.dart

@@ -0,0 +1,17 @@
+// Copyright 2019 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:args/args.dart';
+
+import 'l10n_cli.dart' as l10n_cli;
+
+void main(List<String> arguments) {
+  final parser = ArgParser()
+    ..addFlag(
+      'dry-run',
+      help: 'Write the output to stdout.',
+    );
+  final argResults = parser.parse(arguments);
+  l10n_cli.englishArbsToXmls(isDryRun: argResults['dry-run'] as bool);
+}