Add a utility function to parse annotations in a test file.

lib/src/util/dart.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 unittest.util.dart;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
 
+import 'package:analyzer/analyzer.dart';
 import 'package:path/path.dart' as p;
 
 import 'io.dart';
 import 'isolate_wrapper.dart';
 import 'remote_exception.dart';
 
 /// Runs [code] in an isolate.
 ///
 /// [code] should be the contents of a Dart entrypoint. It may contain imports;
 /// they will be resolved in the same context as the host isolate. [message] is
@@ skipping 42 matching lines @@
   Isolate.spawnUri(Uri.parse(message['uri']), [], message['message'],
           packageRoot: packageRoot)
       .then((_) => replyTo.send({'type': 'success'}))
       .catchError((error, stackTrace) {
     replyTo.send({
       'type': 'error',
       'error': RemoteException.serialize(error, stackTrace)
     });
   });
 }
+
+/// Parse all the annotations at the beginning of a Dart file.
+///
+/// This will parse annotations until the first non-annotation production is
+/// reached.
+List<Annotation> parseAnnotations(String path) {
+  var contents = new File(path).readAsStringSync();
+  var directives = parseDirectives(contents, name: path).directives;
+  return directives.isEmpty ? [] : directives.first.metadata;
+}