--- a/toolkit/components/url-classifier/tests/unit/head_urlclassifier.js
+++ b/toolkit/components/url-classifier/tests/unit/head_urlclassifier.js
@@ -301,17 +301,16 @@ subsExist: function(urls, cb)
 {
   // XXX: there's no interface for checking items in the subs table
   cb();
 },
 
 urlExistInMultipleTables: function(data, cb)
 {
   this.checkTables(data["url"], data["tables"], cb);
-  cb();
 }
 
 };
 
 /**
  * Check a set of assertions against the gAssertions table.
  */
 function checkAssertions(assertions, doneCallback)