How to use birdy as the client in PyWPS tests

[huard]

Description

I'd like to write unit tests for PyWPS processes that use birdy as the client for the tested Service. At the moment, unit tests use this pattern

client = client_for(
            Service(processes=[ProcessClass()], cfgfiles=CFG_FILE)
        )

I would like to be able to do

client = birdy.WPSClient(Service(processes=[ProcessClass()], cfgfiles=CFG_FILE))