Webob needs body to calc Content-Length (bug 1016171)

- Refactored render_response() and added relevant tests

Change-Id: I121e8cc641fe11a036106cbfd206f0aa1f6da560

keystone/common/wsgi.py

@@ -490,17 +490,22 @@ class ExtensionRouter(Router):
         return _factory
 
 
-def render_response(body=None, status=(200, 'OK'), headers=None):
+def render_response(body=None, status=None, headers=None):
     """Forms a WSGI response."""
-    resp = webob.Response()
-    resp.status = '%s %s' % status
-    resp.headerlist = headers or [('Content-Type', 'application/json'),
-                                  ('Vary', 'X-Auth-Token')]
+    headers = headers or []
+    headers.append(('Vary', 'X-Auth-Token'))
 
-    if body is not None:
-        resp.body = jsonutils.dumps(body, cls=utils.SmarterEncoder)
+    if body is None:
+        body = ''
+        status = status or (204, 'No Content')
+    else:
+        body = jsonutils.dumps(body, cls=utils.SmarterEncoder)
+        headers.append(('Content-Type', 'application/json'))
+        status = status or (200, 'OK')
 
-    return resp
+    return webob.Response(body=body,
+                          status='%s %s' % status,
+                          headerlist=headers)
 
 
 def render_exception(error):

tests/test_wsgi.py

@@ -47,3 +47,32 @@ class ApplicationTest(test.TestCase):
         req = self._make_request(url='/?1=2')
         resp = req.get_response(app)
         self.assertEqual(jsonutils.loads(resp.body), {'1': '2'})
+
+    def test_render_response(self):
+        data = {'attribute': 'value'}
+        body = '{"attribute": "value"}'
+
+        resp = wsgi.render_response(body=data)
+        self.assertEqual(resp.status, '200 OK')
+        self.assertEqual(resp.status_int, 200)
+        self.assertEqual(resp.body, body)
+        self.assertEqual(resp.headers.get('Vary'), 'X-Auth-Token')
+        self.assertEqual(resp.headers.get('Content-Length'), str(len(body)))
+
+    def test_render_response_custom_status(self):
+        resp = wsgi.render_response(status=(501, 'Not Implemented'))
+        self.assertEqual(resp.status, '501 Not Implemented')
+        self.assertEqual(resp.status_int, 501)
+
+    def test_render_response_custom_headers(self):
+        resp = wsgi.render_response(headers=[('Custom-Header', 'Some-Value')])
+        self.assertEqual(resp.headers.get('Custom-Header'), 'Some-Value')
+        self.assertEqual(resp.headers.get('Vary'), 'X-Auth-Token')
+
+    def test_render_response_no_body(self):
+        resp = wsgi.render_response()
+        self.assertEqual(resp.status, '204 No Content')
+        self.assertEqual(resp.status_int, 204)
+        self.assertEqual(resp.body, '')
+        self.assertEqual(resp.headers.get('Content-Length'), '0')
+        self.assertEqual(resp.headers.get('Content-Type'), None)