diff --git a/pubspec.yaml b/pubspec.yaml
index 3438955a2dc3d8b4455be7af0bc0c0bb07033603..730808d8e67a2fe8a29a48568a46339c36aa8783 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: test
-version: 0.12.16-dev
+version: 0.12.15+8
 author: Dart Team <misc@dartlang.org>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/test
diff --git a/test/util/forkable_stream_test.dart b/test/util/forkable_stream_test.dart
index c08df9d46b6c90e74539b355c57627c778c796bd..e4b5bdca0ea1d7c15b59b42d8d003759404450de 100644
--- a/test/util/forkable_stream_test.dart
+++ b/test/util/forkable_stream_test.dart
@@ -287,19 +287,19 @@ void main() {
       var sub2 = fork1.listen(null);
       expect(controller.hasListener, isTrue);
 
-      expect(sub1.cancel(), isNull);
+      expect(sub1.cancel(), completion(isNull));
       await flushMicrotasks();
       expect(controller.hasListener, isTrue);
 
-      expect(sub2.cancel(), isNull);
+      expect(sub2.cancel(), completion(isNull));
       await flushMicrotasks();
       expect(controller.hasListener, isTrue);
 
-      expect(fork2.listen(null).cancel(), isNull);
+      expect(fork2.listen(null).cancel(), completion(isNull));
       await flushMicrotasks();
       expect(controller.hasListener, isTrue);
 
-      expect(fork3.listen(null).cancel(), isNull);
+      expect(fork3.listen(null).cancel(), completion(isNull));
       await flushMicrotasks();
       expect(controller.hasListener, isTrue);