Incorporating nweiz' feedback.

pkg/unittest/test/with_test_environment_test.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.
 
 library unittest.with_test_environment_test;
 
 import 'dart:async';
 import 'package:unittest/unittest.dart';
 
 class TestConfiguration extends SimpleConfiguration {
   final Completer _completer = new Completer();
   List<TestCase> _results;
 
   TestConfiguration();
 
   void onSummary(int passed, int failed, int errors, List<TestCase> results,
                  String uncaughtError) {
     super.onSummary(passed, failed, errors, results, uncaughtError);
     _results = results;
   }
 
   Future get done => _completer.future;
 
   onDone(success) {
-    new Future.sync(() {
-      super.onDone(success);
-    }).then((_) => _completer.complete(_))
-    .catchError((error, stack) => _completer.completeError(error, stack));
+    new Future.sync(() => super.onDone(success))
+        .then(_completer.complete)
+        .catchError(_completer.completeError);
   }
 
   bool checkIfTestRan(String testName) {
-    for (final t in _results) {
-      if (t.description == testName) {
-        return true;
-      }
-    }
-    return false;
+    return _results.any((test) => test.description == testName);
   }
 }
 
 Future runUnittests(Function callback) {
   var config = new TestConfiguration();
   unittestConfiguration = config;
   callback();
 
   return config.done;
 }
@@ skipping 39 matching lines @@
   });
 
   // Third test that we can run with two nested test environments.
   withTestEnvironment(() {
     runUnittests(runTests);
     withTestEnvironment(() {
       runUnittests(runTests1);
     });
   });
 }