selftests: forwarding: devlink: Add functionality for trap exceptions test

Add common part of all the tests - check devlink status to ensure that
packets were trapped.
Signed-off-by: Amit Cohen <amitc@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/forwarding/devlink_lib.sh

@@ -356,6 +356,18 @@ devlink_trap_group_stats_idle_test()
 	fi
 }
 
+devlink_trap_exception_test()
+{
+	local trap_name=$1; shift
+	local group_name=$1; shift
+
+	devlink_trap_stats_idle_test $trap_name
+	check_fail $? "Trap stats idle when packets should have been trapped"
+
+	devlink_trap_group_stats_idle_test $group_name
+	check_fail $? "Trap group idle when packets should have been trapped"
+}
+
 devlink_trap_drop_test()
 {
 	local trap_name=$1; shift