diff --git a/packages/mongo/observe_changes_tests.js b/packages/mongo/observe_changes_tests.js
index 7678e91950..0fe94d2ebf 100644
--- a/packages/mongo/observe_changes_tests.js
+++ b/packages/mongo/observe_changes_tests.js
@@ -478,7 +478,7 @@ if (Meteor.isServer) {
       self.expects = [];
       self.insert = async function(fields) {
         return coll.insertAsync(
-          Object.assign({ ts: new MongoInternals.MongoTimestamp(0, 0) }, fields)
+          Object.assign({ ts: new MongoInternals.MongoTimestamp({ t: 0, i: 0 }) }, fields)
         );
       };