diff --git a/test/suite/es6/bug_596_1.js b/test/suite/es6/bug_596_1.js
new file mode 100644
index 0000000000..5f742a5df7
--- /dev/null
+++ b/test/suite/es6/bug_596_1.js
@@ -0,0 +1,47 @@
+// Copyright (c) 2014, Thomas Dahlstrom All rights reserved. Redistribution 
+// and use in source and binary forms, with or without modification, are 
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright 
+// notice, this list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright 
+// notice, this list of conditions and the following disclaimer in the 
+// documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its 
+// contributors may be used to endorse or promote products derived from 
+// this software without specific prior written permission.  
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 
+// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
+// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 
+// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
+
+
+/**
+ * @path es6/bug_596_1.js
+ * @description The SortCompare abstract operation calls ToString() for
+ *              identical elements (step 14/15)
+ * @author Thomas Dahlstrom (tdahlstrom@gmail.com)
+ */
+
+var counter = 0;
+var object = {
+    toString: function(){
+        counter++;
+        return "";
+    }
+};
+
+[object, object].sort();
+if (counter < 2) {
+  // sort calls ToString() for each element at least once
+  $ERROR('#1: [object, object].sort(); counter < 22. Actual: ' + (counter));
+}
+
diff --git a/test/suite/es6/bug_596_2.js b/test/suite/es6/bug_596_2.js
new file mode 100644
index 0000000000..3ba1c468b0
--- /dev/null
+++ b/test/suite/es6/bug_596_2.js
@@ -0,0 +1,77 @@
+// Copyright (c) 2014, Thomas Dahlstrom All rights reserved. Redistribution 
+// and use in source and binary forms, with or without modification, are 
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright 
+// notice, this list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright 
+// notice, this list of conditions and the following disclaimer in the 
+// documentation and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its 
+// contributors may be used to endorse or promote products derived from 
+// this software without specific prior written permission.  
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 
+// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
+// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 
+// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
+
+/**
+ * @path es6/bug_596_2.js
+ * @description Array.prototype.sort does not change non-existent elements to
+ *              undefined elements, that means holes are preserved (cf. spec
+ *              text about [[Delete]] and sparse arrays)
+ * @author Thomas Dahlstrom (tdahlstrom@gmail.com)
+ */
+
+var array = ['a',,void 0];
+
+//CHECK#1
+if (array.length !== 3) {
+    $ERROR('#1: array.length !== 3. Actual: ' + (array.length))
+}
+
+//CHECK#2
+if (array.hasOwnProperty('0') !== true) {
+    $ERROR("#2: array.hasOwnProperty('0'). Actual: " + array.hasOwnProperty('0'));
+}
+
+//CHECK#3
+if (array.hasOwnProperty('1') !== false) {
+    $ERROR("#3: array.hasOwnProperty('1'). Actual: " + array.hasOwnProperty('1'));
+}
+
+//CHECK#4
+if (array.hasOwnProperty('2') !== true) {
+    $ERROR("#4: array.hasOwnProperty('2'). Actual: " + array.hasOwnProperty('2'));
+}
+
+array.sort();
+
+//CHECK#5
+if (array.length !== 3) {
+    $ERROR('#5: array.length !== 3. Actual: ' + (array.length))
+}
+
+//CHECK#6
+if (array.hasOwnProperty('0') !== true) {
+    $ERROR("#6: array.hasOwnProperty('0'). Actual: " + array.hasOwnProperty('0'));
+}
+
+//CHECK#7
+if (array.hasOwnProperty('1') !== true) {
+    $ERROR("#7: array.hasOwnProperty('1'). Actual: " + array.hasOwnProperty('1'));
+}
+
+//CHECK#8
+if (array.hasOwnProperty('2') !== false) {
+    $ERROR("#8: array.hasOwnProperty('2'). Actual: " + array.hasOwnProperty('2'));
+}
+