python3 flaskapp.py

or

export FLASK_APP=flaskapp.py
export FLASK_ENV=development
flask run

The above allows lazy loading without rerunning the dev server.

Run all

pytest -v

Running specific test cases

pytest -v test_file.py
pytest -v -k 'my classifier' i.e. (test_register)

To make new test cases the filename must start with test_, class names must end with TestCase and method names must start with test_.