Python Testing Advanced

Advanced Python Testing

Implementing advanced Python testing — from pytest fixtures and conftest through mocking, parametrization, and test infrastructure.

When to Use

• Building robust test suites with pytest
• Implementing reusable fixtures and conftest
• Mocking external dependencies
• Parametric and property-based testing

Testing Patterns

import pytest
from unittest.mock import Mock, patch

@pytest.fixture
def db_session():
    session = create_test_session()
    yield session
    session.close()

@pytest.mark.parametrize("input,expected", [
    (1, 2), (2, 4), (3, 6),
])
def test_double(input, expected):
    assert double(input) == expected

class TestUserAPI:
    @patch('app.api.get_user')
    def test_get_user(self, mock_get):
        mock_get.return_value = {'id': 1, 'name': 'Test'}
        response = client.get('/users/1')
        assert response.status_code == 200

Verification Checklist

• Fixture scope (function, class, module, session) chosen appropriately
• conftest.py for shared fixtures
• Mock objects for external dependencies
• Parametrize for data-driven tests
• Monkeypatch for environment modifications
• Test coverage > 80%