Renames the test file to reflect its changed contents
Ok too many changes between commits, but I've extracted a downloader class to handle single filename downloads. The DownloadManager class wraps this to build more complex behaviour
Refactors test helper methods into the global config file. Starts the process of injecting a Downloader dependency
Completes the Downloader dependency injection - now not sure whether I want it - and Mocks out the DownloadManager tests