How to test this library.

You need to have a file ZendeskConfig.hs with the following content:

module ZendeskConfig where

import Zendesk
import Control.Monad.Logger

rz f = runStdoutLoggingT $ runZendeskT (
                              ZendeskConfig
                                "https://domain.zendesk.com"
                                "username" -- if it's token then username/token
                                "password" -- this is token if you use token
                                Nothing)
                           f

Then run 
# cabal repl

Prelude > :load ZendeskConfig.hs

and you can invoke commands from interactive shell like this:

l <- rz $ getUsers $$ CL.consume