Update cnf-best-practices-openshift-operations.adoc

Author: mwlinca

modules/cnf-best-practices-openshift-operations.adoc

@@ -214,6 +214,8 @@ CNFs must have the least permissions possible and CNFs must implement Network Po
 [IMPORTANT]
 ====
 Applications must define network policies that permit only the minimum network access the application needs to function.
+
+See test case link:https://github.com/test-network-function/cnf-certification-test/blob/main/CATALOG.md#networking-network-policy-deny-all[networking-network-policy-deny-all]
 ====
 
 [id="cnf-best-practices-secrets-management"]