Fix nova migration tests - update nova client microversion to 2.56

This patch includes several changes:
- nova client microversion is updated to 2.56 in order to test properly
  the destination host when VMs are migrated
- tests test_6_migrate_server_with_host and
  test_7_live_migrate_server_with_host are skipped unless tobiko runs on
  an Openstack environment with 3 or more computes, since testing
  VM migration to a specific destination host with only 2 computes is
  not useful
- the disk_over_commit parameter was removed in microversion 2.25, so
  this patch removes it from tobiko
- tests test_8_live_migrate_server_with_block_migration and
  test_9_live_migrate_server_with_no_block_migration are removed because
  the block_migration parameter is deprecated - its default value "auto"
  is added to the tobiko live_migration method

[1] https://docs.openstack.org/nova/latest/reference/api-microversion-history.html

Change-Id: Ia6bd96a69fe8492c49ab085067c738671b81e7b6

tobiko/openstack/nova/_client.py

@@ -38,7 +38,7 @@ NovaHypervisor = typing.Union[novaclient.v2.hypervisors.Hypervisor]
 class NovaClientFixture(_client.OpenstackClientFixture):
 
     def init_client(self, session) -> NovaClient:
-        return novaclient.client.Client('2', session=session)
+        return novaclient.client.Client('2.56', session=session)
 
 
 class NovaClientManager(_client.OpenstackClientManager):
@@ -190,36 +190,20 @@ def live_migrate_server(server: ServerType = None,
                         server_id: str = None,
                         host: str = None,
                         block_migration: bool = None,
-                        disk_over_commit=False,
                         client: NovaClientType = None,
                         **params):
     server_id = get_server_id(server=server, server_id=server_id)
+    params.update(host=host)
     if block_migration is None:
-        # some setups work only with block migration and some only
-        # with without
-        try:
-            return live_migrate_server(server_id=server_id,
-                                       host=host,
-                                       block_migration=False,
-                                       disk_over_commit=disk_over_commit,
-                                       client=client,
-                                       **params)
-        except NotInSharedStorageMigrateServerError:
-            return live_migrate_server(server_id=server_id,
-                                       host=host,
-                                       block_migration=True,
-                                       disk_over_commit=disk_over_commit,
-                                       client=client,
-                                       **params)
+        params.update(block_migration='auto')
     else:
-        params.update(host=host,
-                      block_migration=block_migration,
-                      disk_over_commit=disk_over_commit)
-        LOG.debug(f"Start server '{server_id}' live migration...\n" +
-                  f"{params}")
-        with handle_migration_errors(server_id=server_id, **params):
-            return nova_client(client).servers.live_migrate(server=server_id,
-                                                            **params)
+        params.update(block_migration=block_migration)
+
+    LOG.debug(f"Start server '{server_id}' live migration...\n" +
+              f"{params}")
+    with handle_migration_errors(server_id=server_id, **params):
+        return nova_client(client).servers.live_migrate(server=server_id,
+                                                        **params)
 
 
 @contextlib.contextmanager

tobiko/tests/functional/openstack/test_nova.py

@@ -45,14 +45,14 @@ class ClientTest(testtools.TestCase):
     @nova.skip_if_missing_hypervisors(count=1)
     def test_list_hypervisors(self):
         hypervisor = nova.list_hypervisors().first
-        self.assertIsInstance(hypervisor.id, int)
+        self.assertIsInstance(hypervisor.id, str)
         self.assertTrue(hypervisor.hypervisor_hostname)
         netaddr.IPAddress(hypervisor.host_ip)
 
     @nova.skip_if_missing_hypervisors(count=1)
     def test_list_hypervisors_without_details(self):
         hypervisor = nova.list_hypervisors(detailed=False).first
-        self.assertIsInstance(hypervisor.id, int)
+        self.assertIsInstance(hypervisor.id, str)
         self.assertTrue(hypervisor.hypervisor_hostname)
         self.assertFalse(hasattr(hypervisor, 'host_ip'))
 

tobiko/tests/scenario/nova/test_server.py

@@ -72,27 +72,17 @@ class BaseServerTest(testtools.TestCase):
         self._test_migrate_server(live=True)
 
     @pytest.mark.server_migrate
-    @nova.skip_if_missing_hypervisors(count=2)
+    @nova.skip_if_missing_hypervisors(count=3)
     def test_6_migrate_server_with_host(self):
         """Tests cold migration actually ends on target hypervisor
         """
         self._test_migrate_server_with_host(live=False)
 
     @pytest.mark.server_migrate
-    @nova.skip_if_missing_hypervisors(count=2)
+    @nova.skip_if_missing_hypervisors(count=3)
     def test_7_live_migrate_server_with_host(self):
         self._test_migrate_server_with_host(live=True)
 
-    @pytest.mark.server_migrate
-    @nova.skip_if_missing_hypervisors(count=2)
-    def test_8_live_migrate_server_with_block_migration(self):
-        self._test_migrate_server(live=True, block_migration=True)
-
-    @pytest.mark.server_migrate
-    @nova.skip_if_missing_hypervisors(count=2)
-    def test_9_live_migrate_server_with_no_block_migration(self):
-        self._test_migrate_server(live=True, block_migration=False)
-
     def _test_migrate_server(self,
                              live: bool,
                              block_migration: bool = None):