improved coverage for layouts

lib/layouts.js

@@ -10,9 +10,7 @@ var dateFormat = require('./date_format')
   "colored": function() { return colouredLayout; }, 
   "coloured": function() { return colouredLayout; }, 
   "pattern": function (config) {
-    var pattern = config.pattern || undefined;
-    var tokens = config.tokens || undefined;
-    return patternLayout(pattern, tokens);
+    return patternLayout(config && config.pattern, config && config.tokens);
 	}
 }
 , colours = {
@@ -231,11 +229,7 @@ function patternLayout (pattern, tokens) {
   };
 
   function replaceToken(conversionCharacter, loggingEvent, specifier) {
-    var replacer = replacers[conversionCharacter];
-    if (replacer) {
-      return replacer(loggingEvent, specifier);
-    }
-    return null;
+    return replacers[conversionCharacter](loggingEvent, specifier);
   }
 
   function truncate(truncation, toTruncate) {