diff --git a/test/lisp/net/tramp-tests.el b/test/lisp/net/tramp-tests.el
index 50687dfe993..35b26304bd5 100644
--- a/test/lisp/net/tramp-tests.el
+++ b/test/lisp/net/tramp-tests.el
@@ -7407,6 +7407,8 @@ tramp--test-check-files
 ;; These tests are inspired by Bug#17238.
 (ert-deftest tramp-test41-special-characters ()
   "Check special characters in file names."
+  (tramp--test-instrument-test-case 10
+  (setq tramp-debug-to-file t)
   (skip-unless (tramp--test-enabled))
   (skip-unless (not (getenv "EMACS_HYDRA_CI"))) ; SLOW ~ 245s
   (skip-unless (not (tramp--test-rsync-p)))
@@ -7468,7 +7470,7 @@ tramp-test41-special-characters
     ;; Simplify test in order to speed up.
     (apply #'tramp--test-check-files
 	   (if (tramp--test-expensive-test-p)
-	       files (list (string-join files ""))))))
+	       files (list (string-join files "")))))))

 (tramp--test-deftest-with-stat tramp-test41-special-characters)