Testing with http_fake

[jaaqo]

Hey,

I'm not sure if the http_fake is designed to be used outside this project, but it looked like an easy way to mock for a python novice like me.

https://github.com/Shopify/pyactiveresource/blob/master/pyactiveresource/testing/http_fake.py#L21

This opener install expression seems to bleed outside the test and caused my functional tests' urllib go haywire.

I extended the test class in the Shopify python api to have reset the urllib opener at tearDown. That seemed to fix it. Is there a better way to solve this?