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# Copyright 2012 OpenStack, LLC
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import netaddr

from tempest import clients
from tempest.common.utils.data_utils import rand_name
from tempest import exceptions
import tempest.test


class BaseNetworkTest(tempest.test.BaseTestCase):

    """
    Base class for the Neutron tests that use the Tempest Neutron REST client

    Per the Neutron API Guide, API v1.x was removed from the source code tree
    (docs.openstack.org/api/openstack-network/2.0/content/Overview-d1e71.html)
    Therefore, v2.x of the Neutron API is assumed. It is also assumed that the
    following options are defined in the [network] section of etc/tempest.conf:

        tenant_network_cidr with a block of cidr's from which smaller blocks
        can be allocated for tenant networks

        tenant_network_mask_bits with the mask bits to be used to partition the
        block defined by tenant-network_cidr
    """

    @classmethod
    def setUpClass(cls):
        os = clients.Manager()
        cls.network_cfg = os.config.network
        if not cls.config.service_available.neutron:
            raise cls.skipException("Neutron support is required")
        cls.client = os.network_client
        cls.networks = []
        cls.subnets = []

    @classmethod
    def tearDownClass(cls):
        for subnet in cls.subnets:
            cls.client.delete_subnet(subnet['id'])
        for network in cls.networks:
            cls.client.delete_network(network['id'])

    @classmethod
    def create_network(cls, network_name=None):
        """Wrapper utility that returns a test network."""
        network_name = network_name or rand_name('test-network-')

        resp, body = cls.client.create_network(network_name)
        network = body['network']
        cls.networks.append(network)
        return network

    @classmethod
    def create_subnet(cls, network):
        """Wrapper utility that returns a test subnet."""
        cidr = netaddr.IPNetwork(cls.network_cfg.tenant_network_cidr)
        mask_bits = cls.network_cfg.tenant_network_mask_bits
        # Find a cidr that is not in use yet and create a subnet with it
        body = None
        failure = None
        for subnet_cidr in cidr.subnet(mask_bits):
            try:
                resp, body = cls.client.create_subnet(network['id'],
                                                      str(subnet_cidr))
                break
            except exceptions.BadRequest as e:
                is_overlapping_cidr = 'overlaps with another subnet' in str(e)
                if not is_overlapping_cidr:
                    raise
                # save the failure in case all of the CIDRs are overlapping
                failure = e

        if not body and failure:
            raise failure

        subnet = body['subnet']
        cls.subnets.append(subnet)
        return subnet