2 files changed, 17 insertions, 0 deletions

diff --git a/test/data/emacs-module/mod-test.c b/test/data/emacs-module/mod-test.c
index da298d4e398..258a679b207 100644
--- a/test/data/emacs-module/mod-test.c
+++ b/test/data/emacs-module/mod-test.c
@@ -268,6 +268,16 @@ Fmod_test_string_a_to_b (emacs_env *env, ptrdiff_t nargs, emacs_value args[],
 }
 
 
+/* Return a unibyte string.  */
+static emacs_value
+Fmod_test_return_unibyte (emacs_env *env, ptrdiff_t nargs, emacs_value args[],
+                          void *data)
+{
+  const char *string = "foo\x00zot";
+  return env->make_unibyte_string (env, string, 7);
+}
+
+
 /* Embedded pointers in lisp objects.  */
 
 /* C struct (pointer to) that will be embedded.  */
@@ -750,6 +760,7 @@ emacs_module_init (struct emacs_runtime *ert)
   DEFUN ("mod-test-globref-reordered", Fmod_test_globref_reordered, 0, 0, NULL,
          NULL);
   DEFUN ("mod-test-string-a-to-b", Fmod_test_string_a_to_b, 1, 1, NULL, NULL);
+  DEFUN ("mod-test-return-unibyte", Fmod_test_return_unibyte, 0, 0, NULL, NULL);
   DEFUN ("mod-test-userptr-make", Fmod_test_userptr_make, 1, 1, NULL, NULL);
   DEFUN ("mod-test-userptr-get", Fmod_test_userptr_get, 1, 1, NULL, NULL);
   DEFUN ("mod-test-vector-fill", Fmod_test_vector_fill, 2, 2, NULL, NULL);
diff --git a/test/src/emacs-module-tests.el b/test/src/emacs-module-tests.el
index 1eebb418cf3..621229c62aa 100644
--- a/test/src/emacs-module-tests.el
+++ b/test/src/emacs-module-tests.el
@@ -500,4 +500,10 @@ See Bug#36226."
   (should (eq (mod-test-identity 123) 123))
   (should-not (call-interactively #'mod-test-identity)))
 
+(ert-deftest module/unibyte ()
+  (let ((result (mod-test-return-unibyte)))
+    (should (stringp result))
+    (should (not (multibyte-string-p (mod-test-return-unibyte))))
+    (should (equal result "foo\x00zot"))))
+
 ;;; emacs-module-tests.el ends here