Please add how to write unit tests to the description

Not really an issue, but would be great if this documentation could be extended on how to write unit tests. Also an answer on this SO question would be nice. https://stackoverflow.com/questions/72431865/how-to-write-a-unit-test-for-flask-based-azure-function-app

Start by reviewing the repository's existing documentation and the linked Stack Overflow question about unit testing a Flask-based Azure Function app. The issue names no documentation file or test entry point; done means adding clear guidance on writing unit tests for this sample and addressing the requested question if appropriate.

Written by the indexing model from the issue text.