Added explanatory comment to test

Author: Lukas Müller

tests/test_api.py

@@ -32,6 +32,16 @@ class API(overpass.API):
         def _get_from_overpass(self, query):
             return pickle.load(open(os.path.join(os.path.dirname(__file__), "example.response"), "rb"))
 
+    # The commented code should only be executed once when major changes to the Overpass API and/or to this wrapper are
+    # introduced. One than has to manually verify that the date in the  example.response file from the Overpass API
+    # matches the data in the example.json file generated by this wrapper.
+    #
+    # The reason for this approach is the following: It is not safe to make calls to the actual API in this test as the
+    # API might momentarily be unavailable and the underlying data can also change at any moment. The commented code is
+    # needed to create the example.response and example.json files. The example.response file is subsequently used to
+    # fake the _get_from_overpass method during the tests and the example.json file is the reference that we are
+    # asserting against.
+    #
     # api = overpass.API()
     # osm_geo = api.get("rel(6518385);out body geom;way(10322303);out body geom;node(4927326183);", verbosity='body geom')
     # pickle.dump(api._get_from_overpass("[out:json];rel(6518385);out body geom;way(10322303);out body geom;node(4927326183);out body geom;"),