diff --git a/js/tests/js1_5/extensions/regress-452168.js b/js/tests/js1_5/extensions/regress-452168.js
index 19b84dbaa3c67..6c8cac44ac11f 100755
--- a/js/tests/js1_5/extensions/regress-452168.js
+++ b/js/tests/js1_5/extensions/regress-452168.js
@@ -52,14 +52,20 @@ function test()
   printBugNumber(BUGNUMBER);
   printStatus (summary);
 
-  jit(true);
-  gczeal(2);
+  if (typeof gczeal == 'undefined')
+  {
+      expect = actual = 'Test requires gczeal, skipped.';
+  }
+  else
+  {
+    jit(true);
+    gczeal(2);
 
-  var a, b; gczeal(2); (function() { for (var p in this) { } })();
-
-  gczeal(0);
-  jit(false);
+    var a, b; gczeal(2); (function() { for (var p in this) { } })();
 
+    gczeal(0);
+    jit(false);
+  }
   reportCompare(expect, actual, summary);
 
   exitFunc ('test');
diff --git a/js/tests/js1_6/extensions/regress-455464-04.js b/js/tests/js1_6/extensions/regress-455464-04.js
index 9f0ed12b53378..3812bd2a99ec2 100755
--- a/js/tests/js1_6/extensions/regress-455464-04.js
+++ b/js/tests/js1_6/extensions/regress-455464-04.js
@@ -54,13 +54,20 @@ function test()
   printBugNumber(BUGNUMBER);
   printStatus (summary);
 
-  jit(true);
-  gczeal(2);
+  if (typeof gczeal == 'undefined')
+  {
+      expect = actual = 'Test requires gczeal, skipped.';
+  }
+  else
+  {
+    jit(true);
+    gczeal(2);
 
-  a=b=c=d=0; this.__defineGetter__('g', gc); for each (y in this);
+    a=b=c=d=0; this.__defineGetter__('g', gc); for each (y in this);
 
-  gczeal(0);
-  jit(false);
+    gczeal(0);
+    jit(false);
+  }
 
   reportCompare(expect, actual, summary);