054-flask/docs/wiki/Setup-and-Run.md

Setup and Run

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Requirements

Python 3.13 or newer. Flask is only needed for the web lectures (the optional web extra); pytest is in the dev extra.

Create and use a local .venv

Windows (PowerShell):

python -m venv .venv
.\.venv\Scripts\Activate.ps1
python -m pip install --upgrade pip
python -m pip install -e ".[dev]"

macOS and Linux:

python3 -m venv .venv
source .venv/bin/activate
python -m pip install --upgrade pip
python -m pip install -e ".[dev]"

Run the server

flask --app flask_day_54.presentation.hello run
python -m flask_day_54.presentation.hello

Open http://127.0.0.1:5000/ and stop the server with Ctrl+C.

Run the tests

python -m pytest

What we gained

• One repeatable way to start from a clean checkout: a local .venv, an upgraded pip and an editable install.
• Two ways to start the Flask server, and a test suite that runs without a browser.