Python Testing Quicklist(GPT)¶

1. Create a Test File¶

Name convention: test_<module>.py

Example:
```
calc.py
test_calc.py
```

2. Import the Tools¶

import unittest   # built-in testing framework
import pytest      # external framework (optional, powerful)

Using unittest (Built-in)¶

Basic Structure

import unittest
import calc   # the file you’re testing

class TestCalc(unittest.TestCase):

    def test_add(self):
        self.assertEqual(calc.add(2, 3), 5)

    def test_subtract(self):
        self.assertEqual(calc.subtract(5, 3), 2)

if __name__ == '__main__':
    unittest.main()

Common Assertions

Method	Description
`assertEqual(a, b)`	a == b
`assertNotEqual(a, b)`	a != b
`assertTrue(x)`	bool(x) is True
`assertFalse(x)`	bool(x) is False
`assertIsNone(x)`	x is None
`assertIn(a, b)`	a in b
`assertRaises(Error)`	checks for exceptions

Using pytest (Popular Alternative)¶

Simple Example

def add(a, b):
    return a + b

def test_add():
    assert add(2, 3) == 5

Run tests

pytest

Pytest Extras

pytest -v → verbose
pytest -q → quiet
pytest <file> → run specific file
pytest -k "add" → run tests with “add” in the name
pytest --maxfail=1 --disable-warnings -q → stop on first fail

Best Practices¶

One test_ file per module.
Each test function name starts with test_.
Keep tests independent.
Use descriptive names (e.g. test_add_positive_numbers).
Automate with CI/CD (e.g., GitHub Actions).

Useful Tools¶

Tool	Purpose
`unittest`	Built-in, solid for small/medium projects
`pytest`	Simpler syntax, plugins, better reporting
`nose2`	Successor to nose (older, less used now)
`coverage`	Measures code coverage
`tox`	Test across multiple environments