Add support for --pub-serve.

lib/src/executable.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.
 
 // TODO(nweiz): This is under lib so that it can be used by the unittest dummy
 // package. Once that package is no longer being updated, move this back into
 // bin.
 library test.executable;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
 
 import 'package:args/args.dart';
 import 'package:stack_trace/stack_trace.dart';
+import 'package:yaml/yaml.dart';
 
 import 'backend/test_platform.dart';
 import 'runner/reporter/compact.dart';
 import 'runner/load_exception.dart';
 import 'runner/loader.dart';
 import 'util/exit_codes.dart' as exit_codes;
 import 'util/io.dart';
 import 'utils.dart';
 
 /// The argument parser used to parse the executable arguments.
 final _parser = new ArgParser(allowTrailingOptions: true);
 
+/// Returns whether the current package has a pubspec which uses the
+/// `test/pub_serve` transformer.
+bool get _usesTransformer {
+  if (!new File('pubspec.yaml').existsSync()) return false;
+  var contents = new File('pubspec.yaml').readAsStringSync();
+
+  var yaml;
+  try {
+    yaml = loadYaml(contents);
+  } on FormatException {
+    return false;
+  }
+
+  if (yaml is! Map) return false;
+
+  var transformers = yaml['transformers'];
+  if (transformers == null) return false;
+  if (transformers is! List) return false;
+
+  return transformers.any((transformer) {
+    if (transformer is String) return transformer == 'test/pub_serve';
+    if (transformer is! Map) return false;
+    if (transformer.keys.length != 1) return false;
+    return transformer.keys.single == 'test/pub_serve';
+  });
+}
+
 void main(List<String> args) {
   _parser.addFlag("help", abbr: "h", negatable: false,
       help: "Shows this usage information.");
   _parser.addOption("package-root", hide: true);
   _parser.addOption("name",
       abbr: 'n',
       help: 'A substring of the name of the test to run.\n'
           'Regular expression syntax is supported.');
   _parser.addOption("plain-name",
       abbr: 'N',
       help: 'A plain-text substring of the name of the test to run.');
   _parser.addOption("platform",
       abbr: 'p',
       help: 'The platform(s) on which to run the tests.',
       allowed: TestPlatform.all.map((platform) => platform.identifier).toList(),
       defaultsTo: 'vm',
       allowMultiple: true);
+  _parser.addOption("pub-serve",
+      help: 'The port of a pub serve instance serving "test/".',
+      hide: !supportsPubServe,
+      valueHelp: 'port');
   _parser.addFlag("color", defaultsTo: null,
       help: 'Whether to use terminal colors.\n(auto-detected by default)');
 
   var options;
   try {
     options = _parser.parse(args);
   } on FormatException catch (error) {
     _printUsage(error.message);
     exitCode = exit_codes.usage;
     return;
   }
 
   if (options["help"]) {
     _printUsage();
     return;
   }
 
   var color = options["color"];
   if (color == null) color = canUseSpecialChars;
 
+  var pubServeUrl;
+  if (options["pub-serve"] != null) {
+    pubServeUrl = Uri.parse("http://localhost:${options['pub-serve']}");
+    if (!_usesTransformer) {
+      stderr.write('''
+When using --pub-serve, you must include the "test/pub_serve" transformer in
+your pubspec:
+
+transformers:
+- test/pub_serve:
+    \$include: test/**_test.dart
+''');
+      exitCode = exit_codes.data;
+      return;
+    }
+  }
+
   var platforms = options["platform"].map(TestPlatform.find);
   var loader = new Loader(platforms,
-      packageRoot: options["package-root"], color: color);
+      pubServeUrl: pubServeUrl,
+      packageRoot: options["package-root"],
+      color: color);
+
   new Future.sync(() {
     var paths = options.rest;
     if (paths.isEmpty) {
       if (!new Directory("test").existsSync()) {
         throw new LoadException("test",
             "No test files were passed and the default directory doesn't "
                 "exist.");
       }
       paths = ["test"];
     }
@@ skipping 87 matching lines @@
     output = stderr;
   }
 
   output.write("""$message
 
 Usage: pub run test:test [files or directories...]
 
 ${_parser.usage}
 """);
 }