Add CLI test of "nova server-group-list"

Test case added for nova cli server-group-list

Change-Id: I04212576ca88bc6bf71db2e7ab8bf09d69124fdc
diff --git a/tempest/cli/simple_read_only/test_nova.py b/tempest/cli/simple_read_only/test_nova.py
index a3787ab..1c1ddf1 100644
--- a/tempest/cli/simple_read_only/test_nova.py
+++ b/tempest/cli/simple_read_only/test_nova.py
@@ -145,6 +145,9 @@
     def test_admin_secgroup_list_rules(self):
         self.nova('secgroup-list-rules')
 
+    def test_admin_server_group_list(self):
+        self.nova('server-group-list')
+
     def test_admin_servce_list(self):
         self.nova('service-list')