test list the network(ipv6) ip usage stats

Change-Id: I079444437de87aae9eb0ef582ef78a3bae208234
diff --git a/neutron_tempest_plugin/api/test_network_ip_availability.py b/neutron_tempest_plugin/api/test_network_ip_availability.py
index e798680..22d2fc6 100644
--- a/neutron_tempest_plugin/api/test_network_ip_availability.py
+++ b/neutron_tempest_plugin/api/test_network_ip_availability.py
@@ -175,3 +175,22 @@
 class NetworksIpAvailabilityIPv6Test(NetworksIpAvailabilityIPv4Test):
 
     _ip_version = lib_constants.IP_VERSION_6
+
+    def setUp(self):
+        super(NetworksIpAvailabilityIPv6Test, self).setUp()
+        net_name = data_utils.rand_name('network')
+        self.network = self.create_network(network_name=net_name)
+
+    @decorators.idempotent_id('0d5a03f2-fdb7-4ec3-b746-734c51d74b69')
+    def test_list_ipv6_ip_availability_after_subnet_and_ports(self):
+        subnet = self.create_subnet(self.network, ip_version=self._ip_version,
+                                    enable_dhcp=False)
+        prefix = netaddr.IPNetwork(subnet['cidr']).prefixlen
+        body = self.admin_client.list_network_ip_availabilities()
+        used_ips_before_port_create = self._get_used_ips(self.network, body)
+        self.create_port(self.network)
+        net_availability = self.admin_client.list_network_ip_availabilities()
+        self._assert_total_and_used_ips(
+            used_ips_before_port_create + 1,
+            calc_total_ips(prefix, self._ip_version),
+            self.network, net_availability)