Add logging for response bodies (#11)

tests/test_retrieval.py

@@ -1,5 +1,6 @@
 # -*- encoding: utf-8 -*-
 
+import logging
 import os
 import pytest
 
@@ -12,6 +13,10 @@ from stw_potsdam.canteen_api import MenuParams
 
 ENV_ENABLED = 'ENABLE_API_QUERY'
 
+# Because log messages are automatically part of the Pytest report, below
+# explicitly avoids adding log handlers via logging#basicConfig, for example.
+logging.getLogger().setLevel(logging.DEBUG)
+
 CANTEENS = read_canteen_config()