diff --git a/collects/tests/run-automated-tests.ss b/collects/tests/run-automated-tests.ss
index 6419c52bb6..5951f75c55 100755
--- a/collects/tests/run-automated-tests.ss
+++ b/collects/tests/run-automated-tests.ss
@@ -50,8 +50,8 @@
   (define name (cadr t))
   (define stderr (current-error-port))
   (define (echo fmt . args)
-    (flush (current-output-port))
-    (flush (current-error-port))
+    (flush-output (current-output-port))
+    (flush-output (current-error-port))
     (fprintf stderr ">>> ~a: ~a\n" name (apply format fmt args)))
   (newline stderr)
   (echo "running...")