vmware-nsx/quantum/tests/unit/test_linux_dhcp.py

# vim: tabstop=4 shiftwidth=4 softtabstop=4

# 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 os
import socket

import mock
from oslo.config import cfg
import testtools

from quantum.agent.common import config
from quantum.agent.linux import dhcp
from quantum.openstack.common import jsonutils


class FakeIPAllocation:
    def __init__(self, address):
        self.ip_address = address


class FakePort1:
    id = 'eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee'
    admin_state_up = True
    fixed_ips = [FakeIPAllocation('192.168.0.2')]
    mac_address = '00:00:80:aa:bb:cc'


class FakePort2:
    id = 'ffffffff-ffff-ffff-ffff-ffffffffffff'
    admin_state_up = False
    fixed_ips = [FakeIPAllocation('fdca:3ba5:a17a:4ba3::2')]
    mac_address = '00:00:f3:aa:bb:cc'


class FakePort3:
    id = '44444444-4444-4444-4444-444444444444'
    admin_state_up = True
    fixed_ips = [FakeIPAllocation('192.168.0.3'),
                 FakeIPAllocation('fdca:3ba5:a17a:4ba3::3')]
    mac_address = '00:00:0f:aa:bb:cc'


class FakeV4HostRoute:
    destination = '20.0.0.1/24'
    nexthop = '20.0.0.1'


class FakeV6HostRoute:
    destination = 'gdca:3ba5:a17a:4ba3::/64'
    nexthop = 'gdca:3ba5:a17a:4ba3::1'


class FakeV4Subnet:
    id = 'dddddddd-dddd-dddd-dddd-dddddddddddd'
    ip_version = 4
    cidr = '192.168.0.0/24'
    gateway_ip = '192.168.0.1'
    enable_dhcp = True
    host_routes = [FakeV4HostRoute]
    dns_nameservers = ['8.8.8.8']


class FakeV6Subnet:
    id = 'ffffffff-ffff-ffff-ffff-ffffffffffff'
    ip_version = 6
    cidr = 'fdca:3ba5:a17a:4ba3::/64'
    gateway_ip = 'fdca:3ba5:a17a:4ba3::1'
    enable_dhcp = True
    host_routes = [FakeV6HostRoute]
    dns_nameservers = ['gdca:3ba5:a17a:4ba3::1']


class FakeV4SubnetNoDHCP:
    id = 'eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee'
    ip_version = 4
    cidr = '192.168.1.0/24'
    gateway_ip = '192.168.1.1'
    enable_dhcp = False
    host_routes = []
    dns_nameservers = []


class FakeV4SubnetNoGateway:
    id = 'eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee'
    ip_version = 4
    cidr = '192.168.1.0/24'
    gateway_ip = None
    enable_dhcp = True
    host_routes = []
    dns_nameservers = []


class FakeV4Network:
    id = 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa'
    subnets = [FakeV4Subnet()]
    ports = [FakePort1()]


class FakeV6Network:
    id = 'bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb'
    subnets = [FakeV6Subnet()]
    ports = [FakePort2()]


class FakeDualNetwork:
    id = 'cccccccc-cccc-cccc-cccc-cccccccccccc'
    subnets = [FakeV4Subnet(), FakeV6Subnet()]
    ports = [FakePort1(), FakePort2(), FakePort3()]


class FakeDualNetworkSingleDHCP:
    id = 'cccccccc-cccc-cccc-cccc-cccccccccccc'
    subnets = [FakeV4Subnet(), FakeV4SubnetNoDHCP()]
    ports = [FakePort1(), FakePort2(), FakePort3()]


class FakeV4NoGatewayNetwork:
    id = 'cccccccc-cccc-cccc-cccc-cccccccccccc'
    subnets = [FakeV4SubnetNoGateway()]
    ports = [FakePort1()]


class TestDhcpBase(testtools.TestCase):
    def test_base_abc_error(self):
        self.assertRaises(TypeError, dhcp.DhcpBase, None)

    def test_restart(self):
        class SubClass(dhcp.DhcpBase):
            def __init__(self):
                dhcp.DhcpBase.__init__(self, None, None, None)
                self.called = []

            def enable(self):
                self.called.append('enable')

            def disable(self, retain_port=False):
                self.called.append('disable %s' % retain_port)

            def reload_allocations(self):
                pass

            @property
            def active(self):
                return True

        c = SubClass()
        c.restart()
        self.assertEqual(c.called, ['disable True', 'enable'])


class LocalChild(dhcp.DhcpLocalProcess):
    PORTS = {4: [4], 6: [6]}

    def __init__(self, *args, **kwargs):
        super(LocalChild, self).__init__(*args, **kwargs)
        self.called = []

    def reload_allocations(self):
        self.called.append('reload')

    def restart(self):
        self.called.append('restart')

    def spawn_process(self):
        self.called.append('spawn')


class TestBase(testtools.TestCase):
    def setUp(self):
        super(TestBase, self).setUp()
        root = os.path.dirname(os.path.dirname(__file__))
        args = ['--config-file',
                os.path.join(root, 'etc', 'quantum.conf.test')]
        self.conf = config.setup_conf()
        self.conf.register_opts(dhcp.OPTS)
        self.conf.register_opt(
            cfg.StrOpt('dhcp_lease_relay_socket',
                       default='$state_path/dhcp/lease_relay'))
        self.conf.register_opt(cfg.BoolOpt('enable_isolated_metadata',
                                           default=True))
        self.conf(args=args)
        self.conf.set_override('state_path', '')
        self.conf.use_namespaces = True

        self.replace_p = mock.patch('quantum.agent.linux.utils.replace_file')
        self.execute_p = mock.patch('quantum.agent.linux.utils.execute')
        self.addCleanup(self.execute_p.stop)
        self.safe = self.replace_p.start()
        self.addCleanup(self.replace_p.stop)
        self.execute = self.execute_p.start()


class TestDhcpLocalProcess(TestBase):
    def test_active(self):
        dummy_cmd_line = 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa'
        self.execute.return_value = (dummy_cmd_line, '')
        with mock.patch.object(LocalChild, 'pid') as pid:
            pid.__get__ = mock.Mock(return_value=4)
            lp = LocalChild(self.conf, FakeV4Network())
            self.assertTrue(lp.active)
            self.execute.assert_called_once_with(['cat', '/proc/4/cmdline'],
                                                 'sudo')

    def test_active_none(self):
        dummy_cmd_line = 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa'
        self.execute.return_value = (dummy_cmd_line, '')
        with mock.patch.object(LocalChild, 'pid') as pid:
            pid.__get__ = mock.Mock(return_value=None)
            lp = LocalChild(self.conf, FakeV4Network())
            self.assertFalse(lp.active)

    def test_active_cmd_mismatch(self):
        dummy_cmd_line = 'bbbbbbbb-bbbb-bbbb-aaaa-aaaaaaaaaaaa'
        self.execute.return_value = (dummy_cmd_line, '')
        with mock.patch.object(LocalChild, 'pid') as pid:
            pid.__get__ = mock.Mock(return_value=4)
            lp = LocalChild(self.conf, FakeV4Network())
            self.assertFalse(lp.active)
            self.execute.assert_called_once_with(['cat', '/proc/4/cmdline'],
                                                 'sudo')

    def test_get_conf_file_name(self):
        tpl = '/dhcp/aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa/dev'
        with mock.patch('os.path.isdir') as isdir:
            isdir.return_value = False
            with mock.patch('os.makedirs') as makedirs:
                lp = LocalChild(self.conf, FakeV4Network())
                self.assertEqual(lp.get_conf_file_name('dev'), tpl)
                self.assertFalse(makedirs.called)

    def test_get_conf_file_name_ensure_dir(self):
        tpl = '/dhcp/aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa/dev'
        with mock.patch('os.path.isdir') as isdir:
            isdir.return_value = False
            with mock.patch('os.makedirs') as makedirs:
                lp = LocalChild(self.conf, FakeV4Network())
                self.assertEqual(lp.get_conf_file_name('dev', True), tpl)
                self.assertTrue(makedirs.called)

    def test_enable_already_active(self):
        delegate = mock.Mock()
        delegate.setup.return_value = 'tap0'
        with mock.patch.object(LocalChild, 'active') as patched:
            patched.__get__ = mock.Mock(return_value=True)
            lp = LocalChild(self.conf, FakeV4Network(),
                            device_delegate=delegate)
            lp.enable()

            self.assertEqual(lp.called, ['restart'])

    def test_enable(self):
        delegate = mock.Mock(return_value='tap0')
        attrs_to_mock = dict(
            [(a, mock.DEFAULT) for a in
            ['active', 'get_conf_file_name', 'interface_name']]
        )

        with mock.patch.multiple(LocalChild, **attrs_to_mock) as mocks:
            mocks['active'].__get__ = mock.Mock(return_value=False)
            mocks['get_conf_file_name'].return_value = '/dir'
            mocks['interface_name'].__set__ = mock.Mock()
            lp = LocalChild(self.conf,
                            FakeDualNetwork(),
                            device_delegate=delegate)
            lp.enable()

            delegate.assert_has_calls(
                [mock.call.setup(mock.ANY, reuse_existing=True)])
            self.assertEqual(lp.called, ['spawn'])
            self.assertTrue(mocks['interface_name'].__set__.called)

    def test_disable_not_active(self):
        attrs_to_mock = dict([(a, mock.DEFAULT) for a in
                              ['active', 'interface_name', 'pid']])
        with mock.patch.multiple(LocalChild, **attrs_to_mock) as mocks:
            mocks['active'].__get__ = mock.Mock(return_value=False)
            mocks['pid'].__get__ = mock.Mock(return_value=5)
            mocks['interface_name'].__get__ = mock.Mock(return_value='tap0')
            with mock.patch.object(dhcp.LOG, 'debug') as log:
                lp = LocalChild(self.conf, FakeDualNetwork())
                lp.disable()
                msg = log.call_args[0][0]
                self.assertIn('stale', msg)

    def test_disable_unknown_network(self):
        attrs_to_mock = dict([(a, mock.DEFAULT) for a in
                              ['active', 'interface_name', 'pid']])
        with mock.patch.multiple(LocalChild, **attrs_to_mock) as mocks:
            mocks['active'].__get__ = mock.Mock(return_value=False)
            mocks['pid'].__get__ = mock.Mock(return_value=None)
            mocks['interface_name'].__get__ = mock.Mock(return_value='tap0')
            with mock.patch.object(dhcp.LOG, 'debug') as log:
                lp = LocalChild(self.conf, FakeDualNetwork())
                lp.disable()
                msg = log.call_args[0][0]
                self.assertIn('No DHCP', msg)

    def test_disable_retain_port(self):
        attrs_to_mock = dict([(a, mock.DEFAULT) for a in
                              ['active', 'interface_name', 'pid']])
        delegate = mock.Mock()
        network = FakeDualNetwork()
        with mock.patch.multiple(LocalChild, **attrs_to_mock) as mocks:
            mocks['active'].__get__ = mock.Mock(return_value=True)
            mocks['pid'].__get__ = mock.Mock(return_value=5)
            mocks['interface_name'].__get__ = mock.Mock(return_value='tap0')
            lp = LocalChild(self.conf, network, device_delegate=delegate,
                            namespace='qdhcp-ns')
            lp.disable(retain_port=True)

        self.assertFalse(delegate.called)
        exp_args = ['ip', 'netns', 'exec', 'qdhcp-ns', 'kill', '-9', 5]
        self.execute.assert_called_once_with(exp_args, root_helper='sudo',
                                             check_exit_code=True)

    def test_disable(self):
        attrs_to_mock = dict([(a, mock.DEFAULT) for a in
                              ['active', 'interface_name', 'pid']])
        delegate = mock.Mock()
        network = FakeDualNetwork()
        with mock.patch.multiple(LocalChild, **attrs_to_mock) as mocks:
            mocks['active'].__get__ = mock.Mock(return_value=True)
            mocks['pid'].__get__ = mock.Mock(return_value=5)
            mocks['interface_name'].__get__ = mock.Mock(return_value='tap0')
            lp = LocalChild(self.conf, network, device_delegate=delegate,
                            namespace='qdhcp-ns')
            lp.disable()

        delegate.assert_has_calls([mock.call.destroy(network, 'tap0')])
        exp_args = ['ip', 'netns', 'exec', 'qdhcp-ns', 'kill', '-9', 5]
        self.execute.assert_called_once_with(exp_args, root_helper='sudo',
                                             check_exit_code=True)

    def test_pid(self):
        with mock.patch('__builtin__.open') as mock_open:
            mock_open.return_value.__enter__ = lambda s: s
            mock_open.return_value.__exit__ = mock.Mock()
            mock_open.return_value.read.return_value = '5'
            lp = LocalChild(self.conf, FakeDualNetwork())
            self.assertEqual(lp.pid, 5)

    def test_pid_no_an_int(self):
        with mock.patch('__builtin__.open') as mock_open:
            mock_open.return_value.__enter__ = lambda s: s
            mock_open.return_value.__exit__ = mock.Mock()
            mock_open.return_value.read.return_value = 'foo'
            lp = LocalChild(self.conf, FakeDualNetwork())
            self.assertIsNone(lp.pid)

    def test_pid_invalid_file(self):
        with mock.patch.object(LocalChild, 'get_conf_file_name') as conf_file:
            conf_file.return_value = '.doesnotexist/pid'
            lp = LocalChild(self.conf, FakeDualNetwork())
            self.assertIsNone(lp.pid)

    def test_get_interface_name(self):
        with mock.patch('__builtin__.open') as mock_open:
            mock_open.return_value.__enter__ = lambda s: s
            mock_open.return_value.__exit__ = mock.Mock()
            mock_open.return_value.read.return_value = 'tap0'
            lp = LocalChild(self.conf, FakeDualNetwork())
            self.assertEqual(lp.interface_name, 'tap0')

    def test_set_interface_name(self):
        with mock.patch('quantum.agent.linux.utils.replace_file') as replace:
            lp = LocalChild(self.conf, FakeDualNetwork())
            with mock.patch.object(lp, 'get_conf_file_name') as conf_file:
                conf_file.return_value = '/interface'
                lp.interface_name = 'tap0'
                conf_file.assert_called_once_with('interface',
                                                  ensure_conf_dir=True)
                replace.assert_called_once_with(mock.ANY, 'tap0')


class TestDnsmasq(TestBase):
    def _test_spawn(self, extra_options):
        def mock_get_conf_file_name(kind, ensure_conf_dir=False):
            return '/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc/%s' % kind

        def fake_argv(index):
            if index == 0:
                return '/usr/local/bin/quantum-dhcp-agent'
            else:
                raise IndexError

        expected = [
            'QUANTUM_RELAY_SOCKET_PATH=/dhcp/lease_relay',
            'QUANTUM_NETWORK_ID=cccccccc-cccc-cccc-cccc-cccccccccccc',
            'ip',
            'netns',
            'exec',
            'qdhcp-ns',
            'dnsmasq',
            '--no-hosts',
            '--no-resolv',
            '--strict-order',
            '--bind-interfaces',
            '--interface=tap0',
            '--except-interface=lo',
            '--pid-file=/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc/pid',
            '--dhcp-hostsfile=/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc/host',
            '--dhcp-optsfile=/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc/opts',
            ('--dhcp-script=/usr/local/bin/quantum-dhcp-agent-'
             'dnsmasq-lease-update'),
            '--leasefile-ro',
            '--dhcp-range=set:tag0,192.168.0.0,static,120s',
            '--dhcp-range=set:tag1,fdca:3ba5:a17a:4ba3::,static,120s']
        expected.extend(extra_options)

        self.execute.return_value = ('', '')
        delegate = mock.Mock()
        delegate.get_interface_name.return_value = 'tap0'

        attrs_to_mock = dict(
            [(a, mock.DEFAULT) for a in
            ['_output_opts_file', 'get_conf_file_name', 'interface_name']]
        )

        with mock.patch.multiple(dhcp.Dnsmasq, **attrs_to_mock) as mocks:
            mocks['get_conf_file_name'].side_effect = mock_get_conf_file_name
            mocks['_output_opts_file'].return_value = (
                '/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc/opts'
            )
            mocks['interface_name'].__get__ = mock.Mock(return_value='tap0')

            with mock.patch.object(dhcp.sys, 'argv') as argv:
                argv.__getitem__.side_effect = fake_argv
                dm = dhcp.Dnsmasq(self.conf, FakeDualNetwork(),
                                  device_delegate=delegate,
                                  namespace='qdhcp-ns')
                dm.spawn_process()
                self.assertTrue(mocks['_output_opts_file'].called)
                self.execute.assert_called_once_with(expected,
                                                     root_helper='sudo',
                                                     check_exit_code=True)

    def test_spawn(self):
        self._test_spawn(['--conf-file=', '--domain=openstacklocal'])

    def test_spawn_cfg_config_file(self):
        self.conf.set_override('dnsmasq_config_file', '/foo')
        self._test_spawn(['--conf-file=/foo', '--domain=openstacklocal'])

    def test_spawn_no_dhcp_domain(self):
        self.conf.set_override('dhcp_domain', '')
        self._test_spawn(['--conf-file='])

    def test_spawn_cfg_dns_server(self):
        self.conf.set_override('dnsmasq_dns_server', '8.8.8.8')
        self._test_spawn(['--conf-file=',
                          '--server=8.8.8.8',
                          '--domain=openstacklocal'])

    def test_output_opts_file(self):
        fake_v6 = 'gdca:3ba5:a17a:4ba3::1'
        fake_v6_cidr = 'gdca:3ba5:a17a:4ba3::/64'
        expected = """
tag:tag0,option:dns-server,8.8.8.8
tag:tag0,option:classless-static-route,20.0.0.1/24,20.0.0.1
tag:tag0,option:router,192.168.0.1
tag:tag1,option:dns-server,%s
tag:tag1,option:classless-static-route,%s,%s""".lstrip() % (fake_v6,
                                                            fake_v6_cidr,
                                                            fake_v6)

        with mock.patch.object(dhcp.Dnsmasq, 'get_conf_file_name') as conf_fn:
            conf_fn.return_value = '/foo/opts'
            dm = dhcp.Dnsmasq(self.conf, FakeDualNetwork())
            dm._output_opts_file()

        self.safe.assert_called_once_with('/foo/opts', expected)

    def test_output_opts_file_single_dhcp(self):
        expected = """
tag:tag0,option:dns-server,8.8.8.8
tag:tag0,option:classless-static-route,20.0.0.1/24,20.0.0.1
tag:tag0,option:router,192.168.0.1""".lstrip()
        with mock.patch.object(dhcp.Dnsmasq, 'get_conf_file_name') as conf_fn:
            conf_fn.return_value = '/foo/opts'
            dm = dhcp.Dnsmasq(self.conf, FakeDualNetworkSingleDHCP())
            dm._output_opts_file()

        self.safe.assert_called_once_with('/foo/opts', expected)

    def test_output_opts_file_no_gateway(self):
        expected = """
tag:tag0,option:classless-static-route,169.254.169.254/32,192.168.1.1
tag:tag0,option:router""".lstrip()

        with mock.patch.object(dhcp.Dnsmasq, 'get_conf_file_name') as conf_fn:
            conf_fn.return_value = '/foo/opts'
            dm = dhcp.Dnsmasq(self.conf, FakeV4NoGatewayNetwork())
            with mock.patch.object(dm, '_make_subnet_interface_ip_map') as ipm:
                ipm.return_value = {FakeV4SubnetNoGateway.id: '192.168.1.1'}

                dm._output_opts_file()
                self.assertTrue(ipm.called)

        self.safe.assert_called_once_with('/foo/opts', expected)

    def test_reload_allocations(self):
        exp_host_name = '/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc/host'
        exp_host_data = """
00:00:80:aa:bb:cc,192-168-0-2.openstacklocal,192.168.0.2
00:00:f3:aa:bb:cc,fdca-3ba5-a17a-4ba3--2.openstacklocal,fdca:3ba5:a17a:4ba3::2
00:00:0f:aa:bb:cc,192-168-0-3.openstacklocal,192.168.0.3
00:00:0f:aa:bb:cc,fdca-3ba5-a17a-4ba3--3.openstacklocal,fdca:3ba5:a17a:4ba3::3
""".lstrip()
        exp_opt_name = '/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc/opts'
        exp_opt_data = "tag:tag0,option:router,192.168.0.1"
        fake_v6 = 'gdca:3ba5:a17a:4ba3::1'
        fake_v6_cidr = 'gdca:3ba5:a17a:4ba3::/64'
        exp_opt_data = """
tag:tag0,option:dns-server,8.8.8.8
tag:tag0,option:classless-static-route,20.0.0.1/24,20.0.0.1
tag:tag0,option:router,192.168.0.1
tag:tag1,option:dns-server,%s
tag:tag1,option:classless-static-route,%s,%s""".lstrip() % (fake_v6,
                                                            fake_v6_cidr,
                                                            fake_v6)

        exp_args = ['ip', 'netns', 'exec', 'qdhcp-ns', 'kill', '-HUP', 5]

        with mock.patch('os.path.isdir') as isdir:
            isdir.return_value = True
            with mock.patch.object(dhcp.Dnsmasq, 'pid') as pid:
                pid.__get__ = mock.Mock(return_value=5)
                dm = dhcp.Dnsmasq(self.conf, FakeDualNetwork(),
                                  namespace='qdhcp-ns')

                method_name = '_make_subnet_interface_ip_map'
                with mock.patch.object(dhcp.Dnsmasq, method_name) as ip_map:
                    ip_map.return_value = {}
                    dm.reload_allocations()
                    self.assertTrue(ip_map.called)

        self.safe.assert_has_calls([mock.call(exp_host_name, exp_host_data),
                                    mock.call(exp_opt_name, exp_opt_data)])
        self.execute.assert_called_once_with(exp_args, root_helper='sudo',
                                             check_exit_code=True)

    def test_make_subnet_interface_ip_map(self):
        with mock.patch('quantum.agent.linux.ip_lib.IPDevice') as ip_dev:
            ip_dev.return_value.addr.list.return_value = [
                {'cidr': '192.168.0.1/24'}
            ]

            dm = dhcp.Dnsmasq(self.conf,
                              FakeDualNetwork(),
                              namespace='qdhcp-ns')

            self.assertEqual(
                dm._make_subnet_interface_ip_map(),
                {FakeV4Subnet.id: '192.168.0.1'}
            )

    def _test_lease_relay_script_helper(self, action, lease_remaining,
                                        path_exists=True):
        relay_path = '/dhcp/relay_socket'
        network_id = 'cccccccc-cccc-cccc-cccc-cccccccccccc'
        mac_address = 'aa:bb:cc:dd:ee:ff'
        ip_address = '192.168.1.9'

        json_rep = jsonutils.dumps(dict(network_id=network_id,
                                        lease_remaining=lease_remaining,
                                        mac_address=mac_address,
                                        ip_address=ip_address))

        environ = {
            'QUANTUM_NETWORK_ID': network_id,
            'QUANTUM_RELAY_SOCKET_PATH': relay_path,
            'DNSMASQ_TIME_REMAINING': '120',
        }

        def fake_environ(name, default=None):
            return environ.get(name, default)

        with mock.patch('os.environ') as mock_environ:
            mock_environ.get.side_effect = fake_environ

            with mock.patch.object(dhcp, 'sys') as mock_sys:
                mock_sys.argv = [
                    'lease-update',
                    action,
                    mac_address,
                    ip_address,
                ]

                with mock.patch('socket.socket') as mock_socket:
                    mock_conn = mock.Mock()
                    mock_socket.return_value = mock_conn

                    with mock.patch('os.path.exists') as mock_exists:
                        mock_exists.return_value = path_exists

                        dhcp.Dnsmasq.lease_update()

                        mock_exists.assert_called_once_with(relay_path)
                        if path_exists:
                            mock_socket.assert_called_once_with(
                                socket.AF_UNIX, socket.SOCK_STREAM)

                            mock_conn.assert_has_calls(
                                [mock.call.connect(relay_path),
                                 mock.call.send(json_rep),
                                 mock.call.close()])

    def test_lease_relay_script_add(self):
        self._test_lease_relay_script_helper('add', 120)

    def test_lease_relay_script_old(self):
        self._test_lease_relay_script_helper('old', 120)

    def test_lease_relay_script_del(self):
        self._test_lease_relay_script_helper('del', 0)

    def test_lease_relay_script_add_socket_missing(self):
        self._test_lease_relay_script_helper('add', 120, False)