driver: add missing use_cache parameter for get_info()

With 19cb8280232 The driver interface has been updated. Now that the
method get_info() has an extra parameter 'use_cache'. That one is
currently not going to be used in lxd driver since we don't cache such
info.

Also, to ensure that the unit tests pass on a machine with lxd installed
as a snap, there are some additional mocks needed.

Change the nova dependency to pull from stable/stein rather than master.

Change-Id: Iaa1c7e9717619b087b98cc5171de2984954ccc6e
Closes-Bug: #1824300
Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@canonical.com>
(cherry picked from commit d0faf787d9)

nova/tests/unit/virt/lxd/test_driver.py

@@ -682,13 +682,15 @@ class LXDDriverTest(test.NoDBTestCase):
 
         self.client.containers.get.assert_called_once_with(instance.name)
 
+    @mock.patch('nova.virt.lxd.common.is_snap_lxd')
     @mock.patch('nova.virt.lxd.driver.network')
     @mock.patch('pwd.getpwuid', mock.Mock(return_value=mock.Mock(pw_uid=1234)))
     @mock.patch('os.getuid', mock.Mock())
     @mock.patch('os.path.exists', mock.Mock(return_value=True))
     @mock.patch('six.moves.builtins.open')
     @mock.patch.object(driver.utils, 'execute')
-    def test_get_console_output(self, execute, _open, _):
+    def test_get_console_output(self, execute, _open, _, is_snap_lxd):
+        is_snap_lxd.return_value = False
         ctx = context.get_admin_context()
         instance = fake_instance.fake_instance_obj(
             ctx, name='test', memory_mb=0)

nova/tests/unit/virt/lxd/test_flavor.py

@@ -48,6 +48,11 @@ class ToProfileTest(test.NoDBTestCase):
         self.CONF2.lxd.pool = None
         self.CONF2.lxd.root_dir = ''
 
+        is_snap_lxd_patch = mock.patch('nova.virt.lxd.common.is_snap_lxd')
+        self.patchers.append(is_snap_lxd_patch)
+        self.is_snap_lxd = is_snap_lxd_patch.start()
+        self.is_snap_lxd.return_value = False
+
     def tearDown(self):
         super(ToProfileTest, self).tearDown()
         for patcher in self.patchers:

nova/virt/lxd/driver.py

@@ -479,7 +479,7 @@ class LXDDriver(driver.ComputeDriver):
         information.
         """
 
-    def get_info(self, instance):
+    def get_info(self, instance, use_cache=True):
         """Return an InstanceInfo object for the instance."""
         try:
             container = self.client.containers.get(instance.name)

tox.ini

@@ -14,7 +14,7 @@ setenv =
   LC_ALL=en_US.utf-8
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-       -egit+https://github.com/openstack/nova.git#egg=nova
+       -egit+https://github.com/openstack/nova.git@stable/stein#egg=nova
 whitelist_externals =
   bash
   find