Add the ability to add tags in the test config.

lib/src/runner/configuration/load.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:io';
 
 import 'package:glob/glob.dart';
 import 'package:path/path.dart' as p;
 import 'package:source_span/source_span.dart';
 import 'package:yaml/yaml.dart';
@@ skipping 42 matching lines @@
   /// Loads the configuration in [_document].
   Configuration load() => _loadTestConfig().merge(_loadRunnerConfig());
 
   /// Loads test configuration (but not runner configuration).
   Configuration _loadTestConfig() {
     var verboseTrace = _getBool("verbose_trace");
     var jsTrace = _getBool("js_trace");
 
     var timeout = _parseValue("timeout", (value) => new Timeout.parse(value));
 
+    var addTags = _getList("add_tags", (tagNode) {
+      _validate(tagNode, "Tags must be strings.", (value) => value is String);
+      _validate(
+          tagNode,
+          "Invalid tag. Tags must be (optionally hyphenated) Dart identifiers.",
+          (value) => value.contains(anchoredHyphenatedIdentifier));
+      return tagNode.value;
+    });
+
     var tags = _getMap("tags", key: (keyNode) {
       _validate(keyNode, "tags key must be a string.",
           (value) => value is String);
       _validate(
           keyNode,
           "Invalid tag. Tags must be (optionally hyphenated) Dart identifiers.",
           (value) => value.contains(anchoredHyphenatedIdentifier));
 
       return keyNode.value;
     }, value: (valueNode) {
       return _nestedConfig(valueNode, "tag value", runnerConfig: false);
     });
 
     return new Configuration(
         verboseTrace: verboseTrace,
         jsTrace: jsTrace,
         timeout: timeout,
+        addTags: addTags,
         tags: tags);
   }
 
   /// Loads runner configuration (but not test configuration).
   ///
   /// If [_runnerConfig] is `false`, this will error if there are any
   /// runner-level configuration fields.
   Configuration _loadRunnerConfig() {
     if (!_runnerConfig) {
       _disallow("reporter");
@@ skipping 167 matching lines @@
     if (!_document.containsKey(field)) return;
     _error("$field isn't supported here.", field);
   }
 
   /// Throws a [SourceSpanFormatException] with [message] about [field].
   void _error(String message, String field) {
     throw new SourceSpanFormatException(
         message, _document.nodes[field].span, _source);
   }
 }