Fix openstack cluster resize

User should be allowed to resize cluster without
changing its size. This patch removes incorrect
constraint defined in openstack cluster resize
implementation.

Change-Id: I7592f76d23a583bcc696a86dc75ada41be6b0f9d

senlinclient/tests/unit/v1/test_cluster.py

@@ -425,14 +425,20 @@ class TestClusterResize(TestCluster):
         self.assertEqual("Only one of 'capacity', 'adjustment' "
                          "and 'percentage' can be specified.", str(error))
 
-    def test_cluster_resize_none_params(self):
+    def test_cluster_resize_only_constraints(self):
         arglist = ['--min-size', '1', '--max-size', '20', 'my_cluster']
         parsed_args = self.check_parser(self.cmd, arglist, [])
-        error = self.assertRaises(exc.CommandError,
-                                  self.cmd.take_action,
-                                  parsed_args)
-        self.assertEqual("At least one of 'capacity', 'adjustment' and "
-                         "'percentage' should be specified.", str(error))
+        self.cmd.take_action(parsed_args)
+        kwargs = {
+            'min_size': 1,
+            'max_size': 20,
+            'adjustment_type': None,
+            'min_step': None,
+            'number': None,
+            'strict': False
+        }
+        self.mock_client.cluster_resize.assert_called_with('my_cluster',
+                                                           **kwargs)
 
     def test_cluster_resize_capacity(self):
         arglist = ['--capacity', '2', '--min-size', '1', '--max-size', '20',

senlinclient/v1/cluster.py

@@ -405,11 +405,6 @@ class ResizeCluster(command.Command):
             raise exc.CommandError(_("Only one of 'capacity', 'adjustment' and"
                                      " 'percentage' can be specified."))
 
-        if sum(v is None for v in (capacity, adjustment, percentage)) == 3:
-            raise exc.CommandError(_("At least one of 'capacity', "
-                                     "'adjustment' and 'percentage' "
-                                     "should be specified."))
-
         action_args['adjustment_type'] = None
         action_args['number'] = None