Plugin config format validation (and tests).

pkg/analyzer/test/src/plugin/plugin_config_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test.src.plugin.plugin_config_test;
 
 import 'package:analyzer/source/analysis_options_provider.dart';
 import 'package:analyzer/src/plugin/plugin_configuration.dart';
 import 'package:unittest/unittest.dart';
+import 'package:yaml/yaml.dart';
 
 main() {
-  group('PluginConfig', () {
+  group('plugin config tests', () {
     group('parsing', () {
       test('plugin map', () {
         const optionsSrc = '''
 analyzer:
   plugins:
     my_plugin1: ^0.1.0 #shorthand 
     my_plugin2:
       version: ^0.2.0
     my_plugin3:
       class_name: MyPlugin
       library_uri: myplugin/myplugin.dart
       path: '/u/disk/src/'
 ''';
         var config = parseConfig(optionsSrc);
         var plugins = pluginsSortedByName(config);
         expect(plugins, hasLength(3));
         expect(plugins[0].name, equals('my_plugin1'));
         expect(plugins[0].version, equals('^0.1.0'));
         expect(plugins[1].name, equals('my_plugin2'));
         expect(plugins[1].version, equals('^0.2.0'));
         expect(plugins[2].name, equals('my_plugin3'));
         expect(plugins[2].version, isNull);
         expect(plugins[2].path, equals('/u/disk/src/'));
         expect(plugins[2].libraryUri, equals('myplugin/myplugin.dart'));
         expect(plugins[2].className, equals('MyPlugin'));
       });
+      test('plugin map (empty)', () {
+        const optionsSrc = '''
+analyzer:
+  plugins:
+    # my_plugin1: ^0.1.0 #shorthand 
+''';
+        var config = parseConfig(optionsSrc);
+        // Commented out plugins shouldn't cause a parse failure.
+        expect(config.plugins.toList(), hasLength(0));

[scheglov, 2015/09/23 17:10:49]

Do you need this toList() invocation?
AFAIK hasLength() works with any object that has "length" getter.

+      });
+      group('errors', () {
+        test('bad format', () {
+          const optionsSrc = '''
+analyzer:
+  plugins:
+    - my_plugin1
+    - my_plugin2
+''';
+          try {
+            parseConfig(optionsSrc);
+            fail('expected PluginConfigFormatException');
+          } on PluginConfigFormatException catch (e) {
+            expect(
+                e.message,
+                equals(
+                    'Unrecognized plugin config format (expected `YamlMap`, got `YamlList`)'));
+            expect(e.yamlNode, new isInstanceOf<YamlList>());
+          }
+        });
+      });
     });
   });
 }
 
 PluginConfig parseConfig(String optionsSrc) {
   var options = new AnalysisOptionsProvider().getOptionsFromString(optionsSrc);
   return new PluginConfig.fromOptions(options);
 }
 
 List<PluginInfo> pluginsSortedByName(PluginConfig config) =>
     config.plugins.toList()..sort((p1, p2) => p1.name.compareTo(p2.name));