Allow empty description for tenants.

Bug: 1025929

(based on the patch submitted by Ivan Bondarev)

* keystoneclient/v2_0/shell.py
  do_tenant_update(): Update description if it is defined.

* keystoneclient/v2_0/tenants.py
  Token.update(), TokenManager.update():
  Update description if it is defined, even if it's empty.

* tests/v2_0/test_tenants.py
  test_update_empty_description(): New test case for empty
  description.

Change-Id: I4c4e93f6bd5d38828685fd55eb1e694f521928e9

keystoneclient/v2_0/shell.py

@@ -140,7 +140,7 @@ def do_tenant_update(kc, args):
     kwargs = {}
     if args.name:
         kwargs.update({'name': args.name})
-    if args.description:
+    if args.description is not None:
         kwargs.update({'description': args.description})
     if args.enabled:
         kwargs.update({'enabled': utils.string_to_bool(args.enabled)})

keystoneclient/v2_0/tenants.py

@@ -38,7 +38,10 @@ class Tenant(base.Resource):
     def update(self, name=None, description=None, enabled=None):
         # Preserve the existing settings; keystone legacy resets these?
         new_name = name if name else self.name
-        new_description = description if description else self.description
+        if description is not None:
+            new_description = description
+        else:
+            new_description = self.description
         new_enabled = enabled if enabled is not None else self.enabled
 
         try:
@@ -116,7 +119,7 @@ class TenantManager(base.ManagerWithFind):
             body['tenant']['name'] = tenant_name
         if enabled is not None:
             body['tenant']['enabled'] = enabled
-        if description:
+        if description is not None:
             body['tenant']['description'] = description
         # Keystone's API uses a POST rather than a PUT here.
         return self._create("/tenants/%s" % tenant_id, body, "tenant")

tests/v2_0/test_tenants.py

@@ -218,6 +218,46 @@ class TenantTests(utils.TestCase):
         self.assertEqual(tenant.description, "I changed you!")
         self.assertFalse(tenant.enabled)
 
+    def test_update_empty_description(self):
+        req_body = {
+            "tenant": {
+                "id": 4,
+                "name": "tenantX",
+                "description": "",
+                "enabled": False,
+            },
+        }
+        resp_body = {
+            "tenant": {
+                "name": "tenantX",
+                "enabled": False,
+                "id": 4,
+                "description": "",
+            },
+        }
+        resp = httplib2.Response({
+            "status": 200,
+            "body": json.dumps(resp_body),
+        })
+
+        httplib2.Http.request(urlparse.urljoin(self.TEST_URL,
+                              'v2.0/tenants/4'),
+                              'POST',
+                              body=json.dumps(req_body),
+                              headers=self.TEST_POST_HEADERS) \
+            .AndReturn((resp, resp['body']))
+        self.mox.ReplayAll()
+
+        tenant = self.client.tenants.update(req_body['tenant']['id'],
+                                            req_body['tenant']['name'],
+                                            req_body['tenant']['description'],
+                                            req_body['tenant']['enabled'])
+        self.assertTrue(isinstance(tenant, tenants.Tenant))
+        self.assertEqual(tenant.id, 4)
+        self.assertEqual(tenant.name, "tenantX")
+        self.assertEqual(tenant.description, "")
+        self.assertFalse(tenant.enabled)
+
     def test_add_user(self):
         resp = httplib2.Response({
             "status": 200,