๐งช Python Testing with unittest and pytest
Testing your Python code prevents bugs from reaching production. pytest makes writing and running tests fast, readable, and enjoyable.
๐ก Quick Tip:
Write tests FIRST (TDD) or right after โ tests written later are often skipped. Aim for >80% coverage with pytest-cov.
๐ป Code Example:
# โโ Using unittest (built-in) โโโโโโโโโโโโโโโโโโโโ import unittest def calculate_pynfinity_xp(actions: list) -> int: """Calculate total XP for a user's actions.""" XP_MAP = {'login': 10, 'challenge': 30, 'pebble': 100} return sum(XP_MAP.get(action, 0) for action in actions) class TestXPCalculation(unittest.TestCase): def test_single_action(self): self.assertEqual(calculate_pynfinity_xp(['login']), 10) def test_multiple_actions(self): result = calculate_pynfinity_xp(['login', 'challenge', 'pebble']) self.assertEqual(result, 140) # 10 + 30 + 100 def test_unknown_action(self): self.assertEqual(calculate_pynfinity_xp(['unknown']), 0) def test_empty_list(self): self.assertEqual(calculate_pynfinity_xp([]), 0) if __name__ == '__main__': unittest.main() # โโ Using pytest (recommended โ pip install pytest) โโ # Save as test_xp.py and run: pytest test_xp.py -v def test_login_xp(): assert calculate_pynfinity_xp(['login']) == 10 def test_full_day_xp(): actions = ['login', 'challenge', 'pebble', 'pebble'] assert calculate_pynfinity_xp(actions) == 240 # 10+30+100+100 def test_invalid_action_gives_zero(): assert calculate_pynfinity_xp(['invalid', 'bogus']) == 0 # Run: pytest test_xp.py -v --tb=short
| Concept | Key Takeaway |
|---|---|
| assertEqual(a, b) | a == b โ most common assertion |
| assertRaises(Error) | Assert that specific exception is raised |
| pytest.fixture | Reusable test setup functions |
| pytest.mark.parametrize | Run same test with multiple inputs |
| pytest -v -k 'test_login' | Run only tests matching pattern |
Keep exploring and happy coding! ๐
