diff --git a/collects/tests/r6rs/io/ports.sls b/collects/tests/r6rs/io/ports.sls
index 5a0ea2ce3b..643ea6fd90 100644
--- a/collects/tests/r6rs/io/ports.sls
+++ b/collects/tests/r6rs/io/ports.sls
@@ -628,7 +628,9 @@
       (test (port-has-port-position? p) #t)
       (test (port-has-set-port-position!? p) #t)
       (test (port-position p) 0)
-      (test/unspec (put-string p "abc"))
+      (test/unspec (put-string p "ab"))
+      (test (port-position p) 2)
+      (test/unspec (put-string p "c"))
       (flush-output-port p)
       (test accum '(#\c #\b #\a))
       (test (port-position p) 3)