added null tests

test/layouts-test.js

@@ -282,14 +282,14 @@ vows.describe('log4js layouts').addBatch({
       test(args, '%x{testFunction}', 'testFunctionToken');
     },
     '%x{doesNotExist} should output the string stored in tokens': function(args) {
-      test(args, '%x{doesNotExist}', '%x{doesNotExist}');
+      test(args, '%x{doesNotExist}', 'null');
     },
     '%x{fnThatUsesLogEvent} should be able to use the logEvent': function(args) {
       test(args, '%x{fnThatUsesLogEvent}', 'DEBUG');
     },
     '%x should output the string stored in tokens': function(args) {
-      test(args, '%x', '%x');
-    },
+      test(args, '%x', 'null');
+    }
   },
   'layout makers': {
     topic: require('../lib/layouts'),