Support returning a Future from a setUp or test body in scheduled_test.

pkg/scheduled_test/test/scheduled_test/wrap_future_test.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.
 
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:scheduled_test/src/mock_clock.dart' as mock_clock;
 
 import '../metatest.dart';
 import '../utils.dart';
 
@@ skipping 26 matching lines @@
   expectTestsPass("wrapFuture should return the value of the wrapped future",
       () {
     test('test', () {
       schedule(() {
         expect(wrapFuture(pumpEventQueue().then((_) => 'foo')),
             completion(equals('foo')));
       });
     });
   });
 
+  expectTestsPass("a returned future should be implicitly wrapped",
+      () {
+    test('test', () {
+      var futureComplete = false;
+      currentSchedule.onComplete.schedule(() => expect(futureComplete, isTrue));
+
+      return pumpEventQueue().then((_) => futureComplete = true);
+    });
+  });
+
+  expectTestsPass("a returned future should not block the schedule",
+      () {
+    test('test', () {
+      var futureComplete = false;
+      schedule(() => expect(futureComplete, isFalse));
+
+      return pumpEventQueue().then((_) => futureComplete = true);
+    });
+  });
+
   expectTestsPass("wrapFuture should pass through the error of the wrapped "
       "future", () {
     var error;
     test('test 1', () {
       schedule(() {
         wrapFuture(pumpEventQueue().then((_) {
           throw 'error';
         })).catchError(wrapAsync((e) {
           error = e;
         }));
@@ skipping 17 matching lines @@
         throw 'error';
       }));
     });
 
     test('test 2', () {
       expect(errors, everyElement(new isInstanceOf<ScheduleError>()));
       expect(errors.map((e) => e.error), equals(['error']));
     });
   }, passing: ['test 2']);
 }