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

pkg/scheduled_test/test/scheduled_test/set_up_test.dart

Index: pkg/scheduled_test/test/scheduled_test/set_up_test.dart
diff --git a/pkg/scheduled_test/test/scheduled_test/set_up_test.dart b/pkg/scheduled_test/test/scheduled_test/set_up_test.dart
index 1fbf80fa6c9e9c012d0043f319d35c2c9837c10f..2ebf35c88c4d3a4b8d88d17ae91e88dc10653629 100644
--- a/pkg/scheduled_test/test/scheduled_test/set_up_test.dart
+++ b/pkg/scheduled_test/test/scheduled_test/set_up_test.dart
@@ -176,4 +176,31 @@ void main(_, message) {
     });
   });
 
+  expectTestsPass("a future returned by setUp is implicitly wrapped", () {
+    var futureComplete = false;
+    setUp(() => pumpEventQueue().then((_) => futureComplete = true));
+
+    test('test', () {
+      currentSchedule.onComplete.schedule(() => expect(futureComplete, isTrue));
+    });
+  });
+
+  expectTestsPass("a future returned by setUp should not block test()", () {
+    var futureComplete = false;
+    setUp(() => pumpEventQueue().then((_) => futureComplete = true));
+
+    test('test', () {
+      expect(futureComplete, isFalse);
+    });
+  });
+
+  expectTestsPass("a future returned by setUp should not block the schedule",
+      () {
+    var futureComplete = false;
+    setUp(() => pumpEventQueue().then((_) => futureComplete = true));
+
+    test('test', () {
+      schedule(() => expect(futureComplete, isFalse));
+    });
+  });
 }