Remove calls to [new Future] work around issue 11911.

pkg/unittest/lib/src/test_case.dart

 // Copyright (c) 2013, 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.
 
 part of unittest;
 
 /**
  * Represents the state for an individual unit test.
  *
  * Create by calling [test] or [solo_test].
@@ skipping 72 matching lines @@
    * a [Future] that can be used to schedule the next test. If the test runs
    * to completion synchronously, or is disabled, null is returned, to
    * tell unittest to schedule the next test immediately.
    */
   Future _run() {
     if (!enabled) return new Future.value();
 
     _result = _stackTrace = null;
     _message = '';
 
-    var f = (setUp == null) ? new Future.value() : new Future(setUp);
-    return f.catchError(_errorHandler('Setup'))
+    // Avoid calling [new Future] to avoid issue 11911.
+    return new Future.value().then((_) {
+      if (setUp != null) return setUp();
+    }).catchError(_errorHandler('Setup'))
         .then((_) {
           // Skip the test if setup failed.
           if (result != null) return new Future.value();
           _config.onTestStart(this);
           _startTime = new DateTime.now();
           _runningTime = null;
           ++_callbackFunctionsOutstanding;
           return testFunction();
         })
         .catchError(_errorHandler('Test'))
@@ skipping 65 matching lines @@
   void error(String messageText, [stack]) {
     _complete(ERROR, messageText, stack);
   }
 
   void _markCallbackComplete() {
     if (--_callbackFunctionsOutstanding == 0 && !isComplete) {
       pass();
     }
   }
 }