Don't depend on httpbin.org for testing

[sunu]

We use httpbin.org in some of our tests. So the most obvious problem it creates is that you need internet to run the test suite. Secondly, httpbin is spewing random 503 responses these days that make our tests to fail randomly.

https://us.pycon.org/2015/schedule/presentation/344/ has interesting ideas about testing requests without the internet. May be we should use some of that.