Add unit tests for nova.virt.firewall.IpTablesFirewallDriver (Part 1)

There are no unit tests for the base IptablesFirewallDriver.
This patch contains a start of those unit tests.
(This is the first part of the abandoned commit
Ie5372b060da1621927a638af915e15f29e885a4c )

Co-Authored-By:
Jay Pipes <jaypipes@gmail.com>
(cherry picked from commit Ia9ef5ead95508cfb27b53b9899a9cfe97d150662)

Chen Li <shchenli@cn.ibm.com>
(Cherry picked from commit Ie2827051e1795c717f8a7762b932a49d182891cd

Change-Id: I993b27479e893e3fe8c459da0da96a310c6278ae
Partial-bug: #1295889

nova/tests/unit/virt/test_firewall.py

@@ -0,0 +1,87 @@
+#    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 mock
+
+
+from nova import objects
+from nova import test
+from nova.virt import firewall
+
+_IPT_DRIVER_CLS = firewall.IptablesFirewallDriver
+
+
+class TestIptablesFirewallDriver(test.NoDBTestCase):
+    def setUp(self):
+        super(TestIptablesFirewallDriver, self).setUp()
+        self.driver = _IPT_DRIVER_CLS()
+
+    @mock.patch('nova.network.linux_net.iptables_manager')
+    def test_constructor(self, iptm_mock):
+        self.driver.__init__()
+
+        self.assertEqual({}, self.driver.instance_info)
+        self.assertEqual(False, self.driver.dhcp_create)
+        self.assertEqual(False, self.driver.dhcp_created)
+        self.assertEqual(iptm_mock, self.driver.iptables)
+
+        # NOTE(jaypipes): Here we are not testing the IptablesManager
+        # constructor. We are only testing the calls made against the
+        # IptablesManager singleton during initialization of the
+        # IptablesFirewallDriver.
+        expected = [
+            mock.call.add_chain('sg-fallback'),
+            mock.call.add_rule('sg-fallback', '-j DROP'),
+        ]
+        iptm_mock.ipv4.__getitem__.return_value \
+            .assert_has_calls(expected)
+        iptm_mock.ipv6.__getitem__.return_value \
+            .assert_has_calls(expected)
+
+    def test_filter_defer_apply_on(self):
+        with mock.patch.object(self.driver.iptables,
+                               'defer_apply_on') as dao_mock:
+            self.driver.filter_defer_apply_on()
+            dao_mock.assert_called_once_with()
+
+    def test_filter_defer_apply_off(self):
+        with mock.patch.object(self.driver.iptables,
+                               'defer_apply_off') as dao_mock:
+            self.driver.filter_defer_apply_off()
+            dao_mock.assert_called_once_with()
+
+    @mock.patch.object(_IPT_DRIVER_CLS, 'remove_filters_for_instance')
+    def test_unfilter_instance_valid(self, rfii_mock):
+        with mock.patch.object(self.driver, 'instance_info') as ii_mock, \
+            mock.patch.object(self.driver, 'iptables') as ipt_mock:
+            fake_instance = objects.Instance(id=123)
+            ii_mock.pop.return_value = True
+
+            self.driver.unfilter_instance(fake_instance, 'fakenetinfo')
+
+            ii_mock.pop.assert_called_once_with(fake_instance.id, None)
+            rfii_mock.assert_called_once_with(fake_instance)
+            ipt_mock.apply.assert_called_once_with()
+
+    @mock.patch.object(_IPT_DRIVER_CLS, 'remove_filters_for_instance')
+    def test_unfilter_instance_invalid(self, rfii_mock):
+        with mock.patch.object(self.driver, 'instance_info') as ii_mock, \
+            mock.patch.object(self.driver, 'iptables') as ipt_mock:
+            fake_instance = objects.Instance(id=123)
+            ii_mock.pop.return_value = False
+
+            self.driver.unfilter_instance(fake_instance, 'fakenetinfo')
+
+            ii_mock.pop.assert_called_once_with(fake_instance.id, None)
+            self.assertFalse(rfii_mock.called)
+            self.assertFalse(ipt_mock.apply.called)