RecordingDownloader relies on the real downloader and saves the request/response pair into a json file.
MockDownloader uses json files from above and mocks responses for specific requests.

…ables.

If the system property 'downloader' is set that use that specific downloader. This is used from gradle by appending `-Ddownloader=ABCD to the command.
ABCD is one of DownloaderType.
The other variable is the static property `DEFAULT_DOWNLOADER` in DownloaderFactory, which can be easily changed as needed inside the IDE according to development needs`.

Normal workflow would be to first use the recording downloader and afterwards only use mocks, if the requests are always staying the same.

This is needed so that a request is made for each test class when running multiple at once. This way RecordingDownloader records all necessary requests.
This works as long as tests are run sequentially and not in parallel.

Only read those files in MockDownloader