Add a LoadSuite class.

test/runner/browser/firefox_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.
 
 @TestOn("vm")
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
@@ skipping 157 matching lines @@
 """);
     });
 
     test("itself", () {
       var result = _runTest(["-p", "firefox", "test.dart"]);
       expect(result.exitCode, equals(0));
     });
 
     test("alongside another browser", () {
       var result = _runTest(["-p", "firefox", "-p", "chrome", "test.dart"]);
-      expect("Compiling".allMatches(result.stdout), hasLength(1));
+
+      // Only one browser should compile the code.
+      expect(result.stdout.contains("[Chrome] compiling"),
+          isNot(result.stdout.contains("[Firefox] compiling")));
       expect(result.exitCode, equals(0));
     });
   });
 
   test("can run failing tests", () {
     new File(p.join(_sandbox, "test.dart")).writeAsStringSync("""
 import 'package:test/test.dart';
 
 void main() {
   test("failure", () => throw new TestFailure("oh no"));
 }
 """);
 
     var result = _runTest(["-p", "firefox", "test.dart"]);
     expect(result.exitCode, equals(1));
   });
 }
 
 ProcessResult _runTest(List<String> args) =>
     runTest(args, workingDirectory: _sandbox);