Add unit tests

[jhculb]

Currently the repository is not unit tested. This ticket will be complete after the following:

• Testing is implemented
• A selection of possibilities from the firehose are stored in the repository
• Each relevant processing function in widesky_processor is tested
• The widesky_db async psycopg connection is mocked
• Each relevant processing function in widesky_db is tested
• The widesky_db async httpx connection is mocked
• User lookup function is tested

The tests are to be passing.