diff --git a/test/lisp/progmodes/python-tests.el b/test/lisp/progmodes/python-tests.el
index e17bc0df92..7243eb0e59 100644
--- a/test/lisp/progmodes/python-tests.el
+++ b/test/lisp/progmodes/python-tests.el
@@ -2763,6 +2763,13 @@ python-nav-forward-sexp-safe-1
    (python-nav-forward-sexp-safe 1)
    (should (looking-at "$"))))
 
+(ert-deftest python-nav-forward-sexp-nil ()
+  (let ((python-forward-sexp-function nil))
+    (python-tests-with-temp-buffer
+        "'''A docstring.'''"
+      (forward-sexp nil t)
+      (should (= (point) 19)))))
+
 (ert-deftest python-nav-up-list-1 ()
   (python-tests-with-temp-buffer
    "