quota-update to return an error msg for 0 args

If no arguments are provided while executing neutron quota-update
instead of printing the current quota values it will throw an error
message "Must specify new values to update quota"

Added unit test to verify that the exception is raised when no
arguments are provided to quota update

Includes release notes.

DocImpact

Closes-Bug: #1597552

Change-Id: I476991c39eafa16148f0cc3252ae5c26b9c8cbfc

neutronclient/neutron/v2_0/quota.py

@@ -209,6 +209,10 @@ class UpdateQuota(neutronV20.NeutronCommand, show.ShowOne):
                 quota[resource] = self._validate_int(
                     resource,
                     getattr(parsed_args, resource))
+        if not quota:
+            raise exceptions.CommandError(
+                message=_('Must specify a valid resource with new quota '
+                          'value'))
         return {self.resource: quota}
 
     def take_action(self, parsed_args):

neutronclient/tests/unit/test_quota.py

@@ -92,3 +92,11 @@ class CLITestV20Quota(test_cli20.CLITestV20Base):
         self.assertIn('subnet', _str)
         self.assertIn('port', _str)
         self.assertNotIn('subnetpool', _str)
+
+    def test_update_quota_noargs(self):
+        resource = 'quota'
+        cmd = test_quota.UpdateQuota(test_cli20.MyApp(sys.stdout), None)
+        args = [self.test_id]
+        self.assertRaises(exceptions.CommandError, self._test_update_resource,
+                          resource, cmd, self.test_id, args=args,
+                          extrafields=None)

releasenotes/notes/fix-quota-update-zero-args-d596c4169c2d2e30.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Fix CLI quota-update to return an error message for no args
+
+    * ``quota-update`` CLI will return an error message
+      ``Must specify a valid resource with new quota value`` if no
+      argument is provided while executing it. If arguments are
+      provided with CLI, no existing behavior is changed.