diff --git a/spec/core/CallTrackerSpec.js b/spec/core/CallTrackerSpec.js
index 064152be..f997de44 100644
--- a/spec/core/CallTrackerSpec.js
+++ b/spec/core/CallTrackerSpec.js
@@ -37,9 +37,11 @@ describe('CallTracker', function() {
       this1 = {};
     callTracker.track({ object: this0, args: [] });
     callTracker.track({ object: this1, args: [] });
+    callTracker.track({ args: [] });
 
     expect(callTracker.thisFor(0)).toBe(this0);
     expect(callTracker.thisFor(1)).toBe(this1);
+    expect(callTracker.thisFor(2)).toBe(undefined);
   });
 
   it('returns any empty array when there was no call', function() {