diff --git a/tests/test-mstring.c b/tests/test-mstring.c
index 685aa3bc..b17bc6ef 100644
--- a/tests/test-mstring.c
+++ b/tests/test-mstring.c
@@ -384,6 +384,9 @@ static void test0(void)
   string_init (s1);
   string_init (s2);
   
+  size_t h1 = string_hash(s1);
+  assert (h1 != 0);
+
   string_printf (s1, "Hello %d worlds. How do you do? I'm fine. Thank you! The weather is bad today. I should had brought my umbrella. Oh! You can lend me one! Thank you very much! No really thank you. I wouldn't be able to get in time for my job.", 2);
   assert (string_equal_str_p(s1, "Hello 2 worlds. How do you do? I'm fine. Thank you! The weather is bad today. I should had brought my umbrella. Oh! You can lend me one! Thank you very much! No really thank you. I wouldn't be able to get in time for my job."));