Support loading transformer plugins from pub.

sdk/lib/_internal/pub/test/serve/utils.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 pub_tests;
 
 import 'dart:async';
 
 import 'package:http/http.dart' as http;
 import 'package:scheduled_test/scheduled_process.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../test_pub.dart';
 
 /// The pub process running "pub serve".
 ScheduledProcess _pubServer;
 
 /// The ephemeral port assigned to the running server.
 int _port;
 
+/// The code for a transformer that renames ".txt" files to ".out" and adds a
+/// ".out" suffix.
+const REWRITE_TRANSFORMER = """
+import 'dart:async';
+
+import 'package:barback/barback.dart';
+
+class RewriteTransformer extends Transformer {
+  RewriteTransformer();
+
+  String get allowedExtensions => '.txt';
+
+  Future apply(Transform transform) {
+    return transform.primaryInput
+        .then((input) => input.readAsString())
+        .then((contents) {
+      var id = transform.primaryId.changeExtension(".out");
+      transform.addOutput(new Asset.fromString(id, "\$contents.out"));
+    });
+  }
+}
+""";
+
 /// Schedules starting the "pub serve" process.
 ///
 /// If [shouldInstallFirst] is `true`, validates that pub install is run first.
-void startPubServe({bool shouldInstallFirst: false}) {
+/// Returns the `pub serve` process.

[Bob Nystrom, 2013/08/27 22:12:30]

Newline above this.

[nweiz, 2013/08/28 20:45:23]

Done.

+ScheduledProcess startPubServe({bool shouldInstallFirst: false}) {
   // Use port 0 to get an ephemeral port.
   _pubServer = startPub(args: ["serve", "--port=0"]);
 
   if (shouldInstallFirst) {
     expect(_pubServer.nextLine(),
         completion(startsWith("Dependencies have changed")));
     expect(_pubServer.nextLine(),
         completion(startsWith("Resolving dependencies...")));
     expect(_pubServer.nextLine(),
         completion(equals("Dependencies installed!")));
   }
 
   expect(_pubServer.nextLine().then(_parsePort), completes);
+  return _pubServer;
 }
 
 /// Parses the port number from the "Serving blah on localhost:1234" line
 /// printed by pub serve.
 void _parsePort(String line) {
   var match = new RegExp(r"localhost:(\d+)").firstMatch(line);
   assert(match != null);
   _port = int.parse(match[1]);
 }
 
@@ skipping 31 matching lines @@
     return _pubServer.nextLine().then((line) {
       if (line.contains("successfully")) return;
 
       // This line wasn't it, so ignore it and keep trying.
       return nextLine();
     });
   }
 
   schedule(nextLine);
 }