What coverage tells you

Coverage measures which lines/branches ran during tests.

Coverage helps you find:

• untested code paths
• dead code

Coverage does not guarantee correctness.

Using pytest-cov

Common setup:

• pytest-covpytest-cov uses coverage.pycoverage.py

Run:

pytest --cov=src --cov-report=term-missing

pytest --cov=src --cov-report=term-missing

HTML report:

pytest --cov=src --cov-report=html

pytest --cov=src --cov-report=html

Good practice

• aim for meaningful coverage
• focus on risk areas
• don’t chase 100% blindly