diff --git a/test/test-utilities.script b/test/test-utilities.script
index 3a02290699d004e1ee009a7547ff477a15144dd1..bb5a6a1cb83cc5aab9414ac2b0aafc4c2b746226 100644
--- a/test/test-utilities.script
+++ b/test/test-utilities.script
@@ -202,8 +202,8 @@
 #+(or clozure (and sbcl (not sb-unicode))) (assert (not +non-base-chars-exist-p+))
 
 (assert (base-string-p (make-string 10 :element-type 'base-char)))
-(assert-equal "abcd" (strcat "a" NIL "bc" "d"))
-(assert-equal "abcd" (reduce/strcat '("a" NIL "bc" "d")))
+(assert-equal "abcd" (strcat "a" nil "bc" "d"))
+(assert-equal "abcd" (reduce/strcat '("a" nil "bc" "d")))
 
 #-non-base-chars-exist-p
 (progn
@@ -217,8 +217,8 @@
   (assert (not (base-string-p (make-string 10 :element-type 'character))))
   (assert (not (base-string-p (unbasify "abc"))))
   (assert (base-string-p (basify "abc")))
-  (assert (not (base-string-p (strcat "a" NIL #\b (unbasify "cd")))))
-  (assert (base-string-p (reduce/strcat (mapcar 'basify '("a" "b" NIL "cd")))))
+  (assert (not (base-string-p (strcat "a" nil #\b (unbasify "cd")))))
+  (assert (base-string-p (reduce/strcat (mapcar 'basify '("a" "b" nil "cd")))))
   (assert (base-string-p (strcat (basify "ab") (basify "cd"))))
   (assert (not (base-string-p (strcat (basify "ab") #\c (unbasify "d")))))
   (assert (base-string-p (strcat (basify "ab") #\c #\d))))