diff -r 000000000000 -r 6474c204b198 js/src/tests/test262/ch11/11.6/11.6.1/S11.6.1_A4_T5.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/test262/ch11/11.6/11.6.1/S11.6.1_A4_T5.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+// Copyright 2009 the Sputnik authors.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/**
+ * The result of an addition is determined using the rules of IEEE 754 double-precision arithmetics
+ *
+ * @path ch11/11.6/11.6.1/S11.6.1_A4_T5.js
+ * @description The sum of two negative zeros is -0. The sum of two positive zeros, or of two zeros of opposite sign is +0
+ */
+
+//CHECK#1
+if (-0 + -0 !== -0 ) {  
+  $ERROR('#1.1: -0 + -0 === 0. Actual: ' + (-0 + -0));
+} else {
+  if (1 / (-0 + -0) !== Number.NEGATIVE_INFINITY) {
+    $ERROR('#1.1: -0 + -0 === - 0. Actual: +0');
+  }
+}
+
+//CHECK#2
+if (0 + -0 !== 0 ) {  
+  $ERROR('#2.1: 0 + -0 === 0. Actual: ' + (0 + -0));
+} else {
+  if (1 / (0 + -0) !== Number.POSITIVE_INFINITY) {
+    $ERROR('#2.2: 0 + -0 === + 0. Actual: -0');
+  }
+}
+
+//CHECK#3
+if (-0 + 0 !== 0 ) {  
+  $ERROR('#3.1: -0 + 0 === 0. Actual: ' + (-0 + 0));
+} else {
+  if (1 / (-0 + 0) !== Number.POSITIVE_INFINITY) {
+    $ERROR('#3.2: -0 + 0 === + 0. Actual: -0');
+  }
+}
+
+//CHECK#4
+if (0 + 0 !== 0 ) {  
+  $ERROR('#4.1: 0 + 0 === 0. Actual: ' + (0 + 0));
+} else {
+  if (1 / (0 + 0) !== Number.POSITIVE_INFINITY) {
+    $ERROR('#4.2: 0 + 0 === + 0. Actual: -0');
+  }
+}
+