FastAPI + SQLAlchemy PyTest coverage

If you try to run pytest-cov with FastAPI and SQLAlchemy, you'll get a bunch of uncovered lines since the default configuration won't work.

An example line that wouldn't be covered in this senario would be items.scalars().first(). First, add the gevent package to your environment, and then add the following lines to your pyproject.toml:

[tool.coverage.run]
concurrency = ["gevent"]

If you don't have a script for running tests in pyproject.toml, you can use something like

test-cov = "python3 -m pytest --cov=./ --cov-report=xml"

Original issue: https://github.com/nedbat/coveragepy/issues/1012