Unit Test Generator — illustrative example

INPUT
Write pytest tests for calculator.add(a, b). It returns the sum of two integers. Required cases: positive values, zero, negative values.

RESULT
# test_calculator.py
import pytest
from calculator import add

@pytest.mark.parametrize("a,b,expected", [(2, 3, 5), (0, 0, 0), (-2, 3, 1)])
def test_add(a, b, expected):
    assert add(a, b) == expected

Run in the project with pytest installed: python -m pytest test_calculator.py

REVIEW
Unit tests should express expected behavior and meaningful boundaries. Do not simply reproduce the implementation's formula in the test.

This is a teaching example, not a live execution record.