Fixes unclear error when no --pool-prefix given

--pool-prefix is required on subnetpool creation.
refactor: removed unused 'for_create' argument in
add_updatable_arguments in subnetpool module.
Closes-bug: #1536479

Change-Id: I79573369cb95c0b090e9ebfea9af40485d968e2f

neutronclient/neutron/v2_0/subnetpool.py

@@ -26,7 +26,7 @@ def _format_prefixes(subnetpool):
         return subnetpool['prefixes']
 
 
-def add_updatable_arguments(parser):
+def add_updatable_arguments(parser, for_create=False):
     parser.add_argument(
         '--description',
         help=_('Description of subnetpool.'))
@@ -42,6 +42,7 @@ def add_updatable_arguments(parser):
     parser.add_argument(
         '--pool-prefix',
         action='append', dest='prefixes',
+        required=for_create,
         help=_('Subnetpool prefixes (This option can be repeated).'))
     utils.add_boolean_argument(
         parser, '--is-default',
@@ -49,7 +50,7 @@ def add_updatable_arguments(parser):
                '(True meaning default).'))
 
 
-def updatable_args2body(parsed_args, body, for_create=True):
+def updatable_args2body(parsed_args, body):
     neutronV20.update_dict(parsed_args, body,
                            ['name', 'prefixes', 'default_prefixlen',
                             'min_prefixlen', 'max_prefixlen', 'is_default',
@@ -79,7 +80,7 @@ class CreateSubnetPool(neutronV20.CreateCommand):
     resource = 'subnetpool'
 
     def add_known_arguments(self, parser):
-        add_updatable_arguments(parser)
+        add_updatable_arguments(parser, for_create=True)
         parser.add_argument(
             '--shared',
             action='store_true',
@@ -139,7 +140,7 @@ class UpdateSubnetPool(neutronV20.UpdateCommand):
 
     def args2body(self, parsed_args):
         body = {}
-        updatable_args2body(parsed_args, body, for_create=False)
+        updatable_args2body(parsed_args, body)
 
         # Parse and update for "address-scope" option/s
         if parsed_args.no_address_scope:

neutronclient/tests/unit/test_cli20_subnetpool.py

@@ -119,6 +119,19 @@ class CLITestV20SubnetPoolJSON(test_cli20.CLITestV20Base):
         self._test_create_resource(resource, cmd, name, myid, args,
                                    position_names, position_values)
 
+    def test_create_subnetpool_no_poolprefix(self):
+        # Should raise an error because --pool-prefix is required
+        resource = 'subnetpool'
+        cmd = subnetpool.CreateSubnetPool(test_cli20.MyApp(sys.stdout), None)
+        name = 'myname'
+        myid = 'myid'
+        args = [name]
+        position_names = ['name']
+        position_values = [name]
+        self.assertRaises(SystemExit, self._test_create_resource, resource,
+                          cmd, name, myid, args, position_names,
+                          position_values)
+
     def test_list_subnetpool_pagination(self):
         cmd = subnetpool.ListSubnetPool(test_cli20.MyApp(sys.stdout), None)
         self.mox.StubOutWithMock(subnetpool.ListSubnetPool, "extend_list")