Add test for testing response headers

Author: josemacassan

tests/test_response_headers.py

@@ -0,0 +1,18 @@
+import threescale_api
+import os
+import pytest
+
+@pytest.fixture(scope="module")
+def client():
+    return threescale_api.ThreeScaleClient(url=os.environ['THREESCALE_PROVIDER_URL'],
+                                         token=os.environ['THREESCALE_PROVIDER_TOKEN'], ssl_verify=False)
+
+def test_x_served_by_ga(client):
+    response = client._rest.get(url=client.url + "/accounts.json")
+    assert response.status_code == 200
+    assert "X-Served-By" not in response.headers
+
+def test_x_served_by_mas(client):
+    response = client._rest.get(url=client.url + "/accounts.json")
+    assert response.status_code == 200
+    assert "X-Served-By" in response.headers