Change checks for test_server test

Changed checks that verify update instance name
to new with non-ASCII characters in different states.

Change-Id: I5fb58e7dbbf6a6196761a6e7bc78bea13028b715
diff --git a/tempest/api/compute/servers/test_servers.py b/tempest/api/compute/servers/test_servers.py
index d2fb652..8e2fbf1 100644
--- a/tempest/api/compute/servers/test_servers.py
+++ b/tempest/api/compute/servers/test_servers.py
@@ -71,9 +71,10 @@
         server = self.client.show_server(server['id'])['server']
         self.assertEqual(key_name, server['key_name'])
 
-    def _update_server_name(self, server_id, status):
+    def _update_server_name(self, server_id, status, prefix_name='server'):
         # The server name should be changed to the the provided value
-        new_name = data_utils.rand_name('server')
+        new_name = data_utils.rand_name(prefix_name)
+
         # Update the server with a new name
         self.client.update_server(server_id,
                                   name=new_name)
@@ -88,8 +89,9 @@
     def test_update_server_name(self):
         # The server name should be changed to the the provided value
         server = self.create_test_server(wait_until='ACTIVE')
-
-        self._update_server_name(server['id'], 'ACTIVE')
+        # Update instance name with non-ASCII characters
+        prefix_name = u'\u00CD\u00F1st\u00E1\u00F1c\u00E9'
+        self._update_server_name(server['id'], 'ACTIVE', prefix_name)
 
     @test.idempotent_id('6ac19cb1-27a3-40ec-b350-810bdc04c08e')
     def test_update_server_name_in_stop_state(self):
@@ -97,7 +99,11 @@
         server = self.create_test_server(wait_until='ACTIVE')
         self.client.stop_server(server['id'])
         waiters.wait_for_server_status(self.client, server['id'], 'SHUTOFF')
-        updated_server = self._update_server_name(server['id'], 'SHUTOFF')
+        # Update instance name with non-ASCII characters
+        prefix_name = u'\u00CD\u00F1st\u00E1\u00F1c\u00E9'
+        updated_server = self._update_server_name(server['id'],
+                                                  'SHUTOFF',
+                                                  prefix_name)
         self.assertNotIn('progress', updated_server)
 
     @test.idempotent_id('89b90870-bc13-4b73-96af-f9d4f2b70077')