Add testcases for overlong encoding of OIDs

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/tests/suites/test_suite_oid.data b/tests/suites/test_suite_oid.data
index 83a39bb..f721b82 100644
--- a/tests/suites/test_suite_oid.data
+++ b/tests/suites/test_suite_oid.data
@@ -113,3 +113,9 @@
 
 OID get numeric string - 32-bit overflow, second subidentifier
 oid_get_numeric_string:"2BC080808000":MBEDTLS_ERR_OID_BUF_TOO_SMALL:""
+
+OID get numeric string - overlong encoding
+oid_get_numeric_string:"8001":MBEDTLS_ERR_OID_BUF_TOO_SMALL:""
+
+OID get numeric string - overlong encoding, second subidentifier
+oid_get_numeric_string:"2B8001":MBEDTLS_ERR_OID_BUF_TOO_SMALL:""