diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index 4d89410..1970b5d 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -1538,7 +1538,7 @@
 
         /* Serial test */
         TEST_ASSERT(crt.authority_key_id.authorityCertSerialNumber.tag ==
-                    MBEDTLS_ASN1_OCTET_STRING);
+                    MBEDTLS_ASN1_INTEGER);
         TEST_ASSERT(crt.authority_key_id.authorityCertSerialNumber.len == serialLength);
     } else {
         TEST_ASSERT(crt.authority_key_id.keyIdentifier.tag == 0);