output function name in AssertionError, if {expected} is a function

Author: cloudhead

lib/assert/error.js

@@ -7,8 +7,10 @@ require('assert').AssertionError.prototype.toString = function () {
 
     function parse(str) {
         return str.replace(/{actual}/g,   inspect(that.actual)).
-                   replace(/{expected}/g, inspect(that.expected)).
-                   replace(/{operator}/g, stylize(that.operator, 'bold'));
+                   replace(/{operator}/g, stylize(that.operator, 'bold')).
+                   replace(/{expected}/g, (that.expected instanceof Function)
+                                          ? that.expected.name
+                                          : inspect(that.expected));
     }
 
     if (this.message) {