5 min read
Testing
Prerequisites: Functions
pytest is the standard testing tool in Python (pip install pytest).
A test is a function whose name starts with test_, containing
assert statements that check expected behavior.
# calculator.py
def add(a, b):
return a + b
# test_calculator.py
from calculator import add
def test_add():
assert add(2, 3) == 5
assert add(-1, 1) == 0
pytest
Running pytest automatically finds every test_* function in the
project and reports which passed or failed — catching the moment a
change breaks something that used to work.