Test is prefs directory needs to be created

main.rkt

@@ -43,6 +43,7 @@
 
 (define (ini->file ini file #:private? [private? #f])
   (let* ((file (get-ini-file file))
+         (_ (make-parent-directory* file))
          (out (if (and private?
                        (memq (system-type 'os) '(unix macosx)))
                   (open-output-file file
@@ -198,4 +199,3 @@
           ini)))))
 
 
-

tests/private.rkt

@@ -17,3 +17,15 @@
  (lambda ()
    (when (file-exists? tmp)
      (delete-file tmp))))
+
+(define tmp-dir
+  (make-temporary-file "simple-ini-parent-~a" 'directory))
+(define nested-file
+  (build-path tmp-dir "preferences" "simple-ini.ini"))
+(dynamic-wind
+ void
+ (lambda ()
+   (ini->file (make-ini) nested-file)
+   (check-true (file-exists? nested-file)))
+ (lambda ()
+   (delete-directory/files tmp-dir)))