Use runAsync for Futures.

pkg/scheduled_test/lib/src/utils.dart

Index: pkg/scheduled_test/lib/src/utils.dart
diff --git a/pkg/scheduled_test/lib/src/utils.dart b/pkg/scheduled_test/lib/src/utils.dart
index 4bd4505f8aefc57f8b88ba0bab43a05b77d813f1..1f1485ab2b20c93757349702f74647cc70ce2c95 100644
--- a/pkg/scheduled_test/lib/src/utils.dart
+++ b/pkg/scheduled_test/lib/src/utils.dart
@@ -52,7 +52,11 @@ String prefixLines(String text, {String prefix: '| ', String firstPrefix}) {
 /// any code to run, as long as it's not waiting on some external event.
 Future pumpEventQueue([int times=20]) {
   if (times == 0) return new Future.value();
-  return new Future.value().then((_) => pumpEventQueue(times - 1));
+  // We use a delayed future to allow runAsync events to finish. The
+  // Future.value or Future() constructors use runAsync themselves and would
+  // therefore not wait for runAsync callbacks that are scheduled after invoking
+  // this method.
+  return new Future.delayed(Duration.ZERO, () => pumpEventQueue(times - 1));
 }
 
 /// Returns whether [iterable1] has the same elements in the same order as