Added ABCMeta class to the InitiatorConnector

This patch adds python ABCMeta class to the InitiatorConnector
for the purposes of defining a required contract that all Connector
objects must adhere to.  Currently, the existing required methods of
connect_volume, disconnect_volume are the 2 required methods that must
be implemented by the child Connector objects.  This will be helpful
for future features and forcing Connectors to adhere to the API
interface Contract.

Change-Id: Ie862ad7f358a70d57eddb2bce269230df3c3cdc7
Implements: blueprint os-brick-abc-connectors

os_brick/initiator/connector.py

@@ -20,6 +20,7 @@ The connectors here are responsible for discovering and removing volumes for
 each of the supported transport protocols.
 """
 
+import abc
 import copy
 import os
 import platform
@@ -106,6 +107,7 @@ def get_connector_properties(root_helper, my_ip, multipath, enforce_multipath,
     return props
 
 
+@six.add_metaclass(abc.ABCMeta)
 class InitiatorConnector(executor.Executor):
     def __init__(self, root_helper, driver=None,
                  execute=putils.execute,
@@ -232,21 +234,36 @@ class InitiatorConnector(executor.Executor):
             return False
         return True
 
+    @abc.abstractmethod
     def connect_volume(self, connection_properties):
         """Connect to a volume.
 
         The connection_properties describes the information needed by
         the specific protocol to use to make the connection.
         """
-        raise NotImplementedError()
+        pass
 
+    @abc.abstractmethod
     def disconnect_volume(self, connection_properties, device_info):
         """Disconnect a volume from the local host.
 
         The connection_properties are the same as from connect_volume.
         The device_info is returned from connect_volume.
         """
-        raise NotImplementedError()
+        pass
+
+
+class FakeConnector(InitiatorConnector):
+
+    fake_path = '/dev/vdFAKE'
+
+    def connect_volume(self, connection_properties):
+        fake_device_info = {'type': 'fake',
+                            'path': self.fake_path}
+        return fake_device_info
+
+    def disconnect_volume(self, connection_properties, device_info):
+        pass
 
 
 class ISCSIConnector(InitiatorConnector):

os_brick/tests/base.py

@@ -17,18 +17,18 @@
 
 import logging
 import os
+import testtools
 
 import fixtures
 import mock
 from oslo_log import log as oslo_logging
 from oslo_utils import strutils
-from oslotest import base
 
 
 LOG = oslo_logging.getLogger(__name__)
 
 
-class TestCase(base.BaseTestCase):
+class TestCase(testtools.TestCase):
 
     """Test case base class for all unit tests."""
 

os_brick/tests/initiator/test_connector.py

@@ -112,15 +112,25 @@ class ConnectorTestCase(base.TestCase):
         self.cmds.append(" ".join(cmd))
         return "", None
 
+    def fake_connection(self):
+        return {
+            'driver_volume_type': 'fake',
+            'data': {
+                'volume_id': 'fake_volume_id',
+                'target_portal': 'fake_location',
+                'target_iqn': 'fake_iqn',
+                'target_lun': 1,
+            }
+        }
+
     def test_connect_volume(self):
-        self.connector = connector.InitiatorConnector(None)
-        self.assertRaises(NotImplementedError,
-                          self.connector.connect_volume, None)
+        self.connector = connector.FakeConnector(None)
+        device_info = self.connector.connect_volume(self.fake_connection())
+        self.assertIn('type', device_info)
+        self.assertIn('path', device_info)
 
     def test_disconnect_volume(self):
-        self.connector = connector.InitiatorConnector(None)
-        self.assertRaises(NotImplementedError,
-                          self.connector.disconnect_volume, None, None)
+        self.connector = connector.FakeConnector(None)
 
     def test_factory(self):
         obj = connector.InitiatorConnector.factory('iscsi', None)
@@ -158,13 +168,13 @@ class ConnectorTestCase(base.TestCase):
                           "bogus", None)
 
     def test_check_valid_device_with_wrong_path(self):
-        self.connector = connector.InitiatorConnector(None)
+        self.connector = connector.FakeConnector(None)
         self.connector._execute = \
             lambda *args, **kwargs: ("", None)
         self.assertFalse(self.connector.check_valid_device('/d0v'))
 
     def test_check_valid_device(self):
-        self.connector = connector.InitiatorConnector(None)
+        self.connector = connector.FakeConnector(None)
         self.connector._execute = \
             lambda *args, **kwargs: ("", "")
         self.assertTrue(self.connector.check_valid_device('/dev'))
@@ -172,7 +182,7 @@ class ConnectorTestCase(base.TestCase):
     def test_check_valid_device_with_cmd_error(self):
         def raise_except(*args, **kwargs):
             raise putils.ProcessExecutionError
-        self.connector = connector.InitiatorConnector(None)
+        self.connector = connector.FakeConnector(None)
         with mock.patch.object(self.connector, '_execute',
                                side_effect=putils.ProcessExecutionError):
             self.assertFalse(self.connector.check_valid_device('/dev'))