Update metatest for the latest test package.

lib/metatest.dart

 // Copyright (c) 2014, 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.
 
 /// A test library for testing test libraries? We must go deeper.
 ///
 /// Since unit testing code tends to use a lot of global state, it can be tough
 /// to test. This library manages it by running each test case in a child
 /// isolate, then reporting the results back to the parent isolate.
 library metatest;
 
 import 'dart:async';
 import 'dart:isolate';
 
 // TODO(nweiz): Stop importing from src when dart-lang/test#48 is fixed.
 import 'package:test/src/backend/declarer.dart';
+import 'package:test/src/backend/live_test.dart';
 import 'package:test/src/backend/state.dart';
 import 'package:test/src/backend/suite.dart';
 import 'package:test/src/runner/engine.dart';
 import 'package:test/test.dart';
 
 /// Declares a test with the given [description] and [body].
 ///
 /// [body] corresponds to the `main` method of a test file. By default, this
 /// expects that all tests defined in [body] pass, but if [passing] is passed,
 /// only tests listed there are expected to pass.
@@ skipping 32 matching lines @@
 }
 
 /// Sets up a test with the given [description] and [body]. After the test runs,
 /// calls [validate] with the result map.
 void _setUpTest(String description, void body(),
     void validate(List<LiveTest> liveTests)) {
   test(description, () async {
     var declarer = new Declarer();
     runZoned(body, zoneValues: {#test.declarer: declarer});
 
-    var engine = new Engine([new Suite(declarer.tests)]);
+    var engine = new Engine.withSuites([new Suite(declarer.tests)]);
     for (var test in engine.liveTests) {
       test.onPrint.listen(print);
     }
     await engine.run();
 
     validate(engine.liveTests);
   });
 }
 
 /// Returns a string description of the test run descibed by [liveTests].
 String _summarizeTests(List<LiveTest> liveTests) {
   var buffer = new StringBuffer();
   for (var liveTest in liveTests) {
     buffer.writeln("${liveTest.state.result}: ${liveTest.test.name}");
     for (var error in liveTest.errors) {
       buffer.writeln(error.error);
       if (error.stackTrace != null) buffer.writeln(error.stackTrace);
     }
   }
   return buffer.toString();
 }