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Testing in Python

This file covers testing strategies, frameworks, and best practices for Python applications.

Testing Frameworks​

  • Most popular Python testing framework
  • Simple syntax and powerful features
  • Extensive plugin ecosystem
  • Great assertion introspection

unittest (Built-in)​

  • Part of Python standard library
  • Class-based test structure
  • Good for traditional unit testing

doctest​

  • Tests embedded in docstrings
  • Great for simple examples
  • Documentation and testing combined

pytest Examples​

# test_math.py
def test_addition():
    assert 2 + 2 == 4

def test_division():
    assert 10 / 2 == 5

# Using fixtures
import pytest

@pytest.fixture
def sample_data():
    return {"name": "John", "age": 30}

def test_sample_data(sample_data):
    assert sample_data["name"] == "John"

Testing Types​

Unit Tests​

  • Test individual functions/methods
  • Fast execution
  • Mock external dependencies

Integration Tests​

  • Test component interactions
  • Database connections
  • API endpoints

End-to-End Tests​

  • Test complete workflows
  • User scenarios
  • Browser automation (Selenium)

Best Practices​

  • Write tests first (TDD)
  • Use descriptive test names
  • Test edge cases and error conditions
  • Mock external services
  • Maintain test independence
  • Use fixtures for setup/teardown
  • Achieve good test coverage

Coverage Analysis​

# Install coverage
pip install coverage

# Run tests with coverage
coverage run -m pytest

# Generate report
coverage report
coverage html

Continuous Integration​

Integrate testing into CI/CD pipelines for automated quality assurance.