diff --git a/test.mes b/test.mes
index a4d0567a..f4431651 100644
--- a/test.mes
+++ b/test.mes
@@ -32,6 +32,10 @@
             ((car t) (display ": pass") (newline) (set! pass (+ pass 1)))
             (#t (display ": fail") (newline) (set! fail (+ fail 1)))))))
 
+(define (guile?) (defined? 'gc))
+(if (guile?)
+    (module-define! (current-module) 'builtin? (lambda (. x) #t)))
+
 (define (seq? a b)
   (or (eq? a b)
       (begin
@@ -124,8 +128,9 @@
 (pass-if "list->vector" (sequal? (list->vector '(a b c)) #(a b c)))
 (pass-if "vector" (sequal? #(vector 0 1 2) #(vector 0 1 2)))
 (pass-if "vector-ref" (seq? (vector-ref #(0 1) 1) 1))
-;;(pass-if "vector-set" (sequal? (let ((v #(0 1))) (vector-set! v 1 'q) v) #(0 q)))
-;;(pass-if "vector-set" (sequal? (let ((v #(0 1))) (vector-set! v 1 'q) v) #()))
+(when (not guile?) ;; hmm guile segfaults
+  (pass-if "vector-set" (equal? (let ((v #(0 1))) (vector-set! v 1 'q) v) #(0 q)))
+  (pass-if "vector-set 2" (not (equal? (let ((v #(0 1))) (vector-set! v 1 'q) v) #()))))
 (pass-if "equal?" (sequal? #(1) #(1)))
 (pass-if "equal?" (not (equal? #() #(1))))
 (pass-if "memq" (sequal? (memq 'a '(a b c)) '(a b c)))
@@ -156,10 +161,6 @@
 ;;        (display ((lambda (x) x) (values 1 2 3)))
 ;;        (newline)))
 
-(define (guile?) (defined? 'gc))
-(if (guile?)
-    (module-define! (current-module) 'builtin? (lambda (. x) #t)))
-
 (pass-if "builtin?" (builtin? eval))
 ;;(pass-if "builtin?" (builtin? cond))
 (pass-if "procedure?" (procedure? builtin?))