Unit Testing

Unit Testing#

Why test?

  • Quality: verify correct behavior across inputs and edge cases

  • Safe refactoring: catch regressions immediately

  • Documentation: tests show exactly how a function is supposed to behave

Getting started with pytest#

pip install pytest

# src/mypkgs/calculate.py
def calculate_area(length, width):
    """Calculate the area of a rectangle."""
    return length * width

# tests/test_calculate.py
from mypkgs.calculate import calculate_area

def test_calculate_area():
    assert calculate_area(2, 3) == 6
    assert calculate_area(0, 5) == 0
    assert calculate_area(-1, 5) == -5

python -m pytest
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