build proper testing framework

[nupfel]

as complexity due to amount of settings combinations have been growing quite a bit, this module needs some decent test framework to cover at least all the most common cases of combinations. at this point it doesn't seem trivial to me anymore how to go ahead with this.

options are:

• start a simple server and generate responses for requests
• hook in between actual sending request and replying with responses so we don't have to start some kind of server
• test against real APIs
• only test internal methods directly with all combinations of inputs
• let inheriting modules do the testing of specific APIs