diff --git a/test/index.html b/test/index.html
index 8246187f6..746662e37 100644
--- a/test/index.html
+++ b/test/index.html
@@ -50,16 +50,16 @@
 				// allow bypassing native checks
 				setProperty(Function.prototype, 'toString', (function() {
 					function wrapper() {
-						setProperty(Function.prototype, 'toString', fnToString);
-						var result = (this === window.ArrayBuffer || this === window.Set)
-							? this.toString()
-							: fnToString.call(this);
-
-						setProperty(Function.prototype, 'toString', wrapper);
+						setProperty(funcProto, 'toString', fnToString);
+						var result = hasOwnProperty.call(this, 'toString') ? this.toString() : fnToString.call(this);
+						setProperty(funcProto, 'toString', wrapper);
 						return result;
 					}
-					var fnToString = Function.prototype.toString;
-					setProperty(Function.prototype, '_toString', fnToString);
+					var funcProto = Function.prototype,
+					    fnToString = funcProto.toString,
+					    hasOwnProperty = Object.prototype.hasOwnProperty;
+
+					setProperty(funcProto, '_toString', fnToString);
 					return wrapper;
 				}()));
 
@@ -95,10 +95,11 @@
 						}
 						return hasOwnProperty.call(this, key);
 					}
-					var hasOwnProperty = Object.prototype.hasOwnProperty,
-					    propertyIsEnumerable = Object.prototype.propertyIsEnumerable;
+					var objectProto = Object.prototype,
+					    hasOwnProperty = objectProto.hasOwnProperty,
+					    propertyIsEnumerable = objectProto.propertyIsEnumerable;
 
-					setProperty(Object.prototype, '_hasOwnProperty', hasOwnProperty);
+					setProperty(objectProto, '_hasOwnProperty', hasOwnProperty);
 					return wrapper;
 				}()));
 
@@ -113,7 +114,7 @@
 
 				setProperty(window, '_ArrayBuffer', window.ArrayBuffer);
 				if (window.ArrayBuffer && window.Uint8Array && !new ArrayBuffer(0).slice) {
-					ArrayBuffer = (function() {
+					ArrayBuffer = (function(_ArrayBuffer) {
 						function constant(value) {
 							return function() {
 								return value;
@@ -122,7 +123,7 @@
 						function ArrayBuffer(byteLength) {
 							var buffer = new _ArrayBuffer(byteLength);
 							buffer.slice = function() {
-								var newBuffer = new _ArrayBuffer(byteLength),
+								var newBuffer = new _ArrayBuffer(this.byteLength),
 								    view = new Uint8Array(newBuffer);
 
 								view.set(new Uint8Array(this));
@@ -138,7 +139,7 @@
 
 						setProperty(ArrayBuffer, 'toString', bufferToString);
 						return ArrayBuffer;
-					}());
+					}(_ArrayBuffer));
 				}
 				setProperty(window, '_Float64Array', window.Float64Array);
 				if (window._ArrayBuffer == window.ArrayBuffer && window._Float64Array) {
@@ -202,8 +203,6 @@
 
 				if (window._ArrayBuffer) {
 					ArrayBuffer = _ArrayBuffer;
-				} else {
-					setProperty(window, 'ArrayBuffer', undefined);
 				}
 				setProperty(window, '_ArrayBuffer', undefined);
 
diff --git a/test/test.js b/test/test.js
index 3d263aa97..691753d4a 100644
--- a/test/test.js
+++ b/test/test.js
@@ -341,10 +341,7 @@
     var _fnToString = funcProto.toString;
     setProperty(funcProto, 'toString', function wrapper() {
       setProperty(funcProto, 'toString', _fnToString);
-      var result = (this === root.ArrayBuffer || this === root.Set)
-        ? this.toString()
-        : _fnToString.call(this);
-
+      var result = _.has(this, 'toString') ? this.toString() : _fnToString.call(this);
       setProperty(funcProto, 'toString', wrapper);
       return result;
     });
@@ -391,7 +388,7 @@
         function ArrayBuffer(byteLength) {
           var buffer = new _ArrayBuffer(byteLength);
           buffer.slice = function() {
-            var newBuffer = new _ArrayBuffer(byteLength),
+            var newBuffer = new _ArrayBuffer(this.byteLength),
                 view = new Uint8Array(newBuffer);
 
             view.set(new Uint8Array(this));