diff --git a/tests/suites/test_suite_x509write.data b/tests/suites/test_suite_x509write.data
index 2c6f59e..2240d82 100644
--- a/tests/suites/test_suite_x509write.data
+++ b/tests/suites/test_suite_x509write.data
@@ -223,5 +223,8 @@
 X509 String to Names #19 (Accept non-ascii hexpairs)
 mbedtls_x509_string_to_names:"C=NL, O=Of\\CCspark, OU=PolarSSL":"C=NL, O=Of\\CCspark, OU=PolarSSL":0
 
+X509 String to Names #20 (Reject empty AttributeValue)
+mbedtls_x509_string_to_names:"C=NL, O=, OU=PolarSSL":"":MBEDTLS_ERR_X509_INVALID_NAME   
+
 Check max serial length
 x509_set_serial_check: