Issue #1936: Make the spy functions non enumerable so that printing it is more concise

lib/sinon/spy.js

@@ -217,9 +217,9 @@ var spyApi = {
         var length = spyLength || funk.length;
         var proxy = createProxy(funk, length);
 
-        extend(proxy, spy);
+        extend.nonEnum(proxy, spy);
         delete proxy.create;
-        extend(proxy, funk);
+        extend.nonEnum(proxy, funk);
 
         proxy.resetHistory();
         proxy.prototype = funk.prototype;

lib/sinon/util/core/extend.js

@@ -51,24 +51,15 @@ var hasDontEnumBug = (function() {
     return join(result, "") !== "0123456789";
 })();
 
-/* Public: Extend target in place with all (own) properties from sources in-order. Thus, last source will
- *         override properties in previous sources.
- *
- * target - The Object to extend
- * sources - Objects to copy properties from.
- *
- * Returns the extended target
- */
-module.exports = function extend(target /*, sources */) {
-    var sources = slice(arguments, 1);
+function extendCommon(target, sources, doCopy) {
     var source, i, prop;
 
     for (i = 0; i < sources.length; i++) {
         source = sources[i];
 
         for (prop in source) {
             if (hasOwnProperty(source, prop)) {
-                target[prop] = source[prop];
+                doCopy(target, source, prop);
             }
         }
 
@@ -80,4 +71,41 @@ module.exports = function extend(target /*, sources */) {
     }
 
     return target;
+}
+
+/** Public: Extend target in place with all (own) properties from sources in-order. Thus, last source will
+ *         override properties in previous sources.
+ *
+ * @arg {Object} target - The Object to extend
+ * @arg {Object[]} sources - Objects to copy properties from.
+ *
+ * @returns {Object} the extended target
+ */
+module.exports = function extend(target /*, sources */) {
+    var sources = slice(arguments, 1);
+
+    return extendCommon(target, sources, function copyValue(dest, source, prop) {
+        dest[prop] = source[prop];
+    });
+};
+
+/** Public: Extend target in place with all (own) properties from sources in-order. Thus, last source will
+ *         override properties in previous sources. Define the properties as non enumerable.
+ *
+ * @arg {Object} target - The Object to extend
+ * @arg {Object[]} sources - Objects to copy properties from.
+ *
+ * @returns {Object} the extended target
+ */
+module.exports.nonEnum = function extendNonEnum(target /*, sources */) {
+    var sources = slice(arguments, 1);
+
+    return extendCommon(target, sources, function copyProperty(dest, source, prop) {
+        Object.defineProperty(dest, prop, {
+            value: source[prop],
+            enumerable: false,
+            configurable: true,
+            writable: true
+        });
+    });
 };