Add test for response headers, X-Served-by

Author: josemacassan

tests/integration/test_integration_response_headers.py

@@ -0,0 +1,5 @@
+
+def test_x_served_by(api):
+    response = api._rest.get(url=api.admin_api_url + '/accounts')
+    assert response.status_code == 200
+    assert "X-Served-By" not in response.headers