Table of Contents

• Quick Start
• When to Use
• Modules
• Core Testing
• Infrastructure & Workflow
• Quality
• Progressive Loading
• Exit Criteria

Python Testing Hub

Testing patterns for pytest, fixtures, mocking, and TDD.

Quick Start

1. Install pytest and dependencies:

   pip install pytest pytest-cov pytest-asyncio pytest-mock
   

   Verification: Run pytest -v pytest-cov to verify.

2. Configure project - Add to pyproject.toml:

   [tool.pytest.ini_options]
   testpaths = ["tests"]
   python_files = ["test_*.py"]
   addopts = "--cov=src --cov-report=html"
   

   Verification: Run pytest -v to verify tests pass.

3. Create first test - In tests/test_example.py:

   def test_basic():
       assert 1 + 1 == 2
   

   Verification: Run pytest -v to verify tests pass.

4. Run tests with coverage:

   pytest --cov=src --cov-report=html
   

   Verification: Run pytest -v --cov=src to verify.

When to Use

• Writing unit tests for Python code
• Setting up test suites and infrastructure
• Implementing test-driven development (TDD)
• Creating integration tests for APIs and services
• Mocking external dependencies and services
• Testing async code and concurrent operations

Modules

This skill provides focused modules for different testing aspects:

Core Testing

• unit-testing - Fundamental unit testing patterns with pytest including AAA pattern, basic test structure, and exception testing
• fixtures-and-mocking - Advanced pytest fixtures, parameterized tests, and mocking patterns for external dependencies
• async-testing - Testing asynchronous Python code with pytest-asyncio including async fixtures and concurrent operation testing

Infrastructure & Workflow

• test-infrastructure - Project configuration for pytest including pyproject.toml setup, test directory structure, and coverage configuration
• testing-workflows - Running tests, CI/CD integration, and automated testing workflows

Quality

• test-quality - Best practices, anti-patterns to avoid, and quality criteria for Python tests

Progressive Loading

Load modules based on project requirements:

• Start with unit-testing for fundamental patterns
• Add fixtures-and-mocking for advanced test setup
• Include test-infrastructure when setting up new projects
• Use testing-workflows for CI/CD integration
• Reference test-quality for best practices
• Apply async-testing for asynchronous code

Exit Criteria

• Tests follow AAA pattern
• Coverage meets project threshold (≥80%)
• All tests independent and reproducible
• CI/CD integration configured
• Clear test naming and organization
• No anti-patterns present
• Fixtures used appropriately
• Mocking only at boundaries

Troubleshooting

Common Issues

Tests not discovered Ensure test files match pattern test_*.py or *_test.py. Run pytest --collect-only to verify.

Import errors Check that the module being tested is in PYTHONPATH or install with pip install -e .

Async tests failing Install pytest-asyncio and decorate test functions with @pytest.mark.asyncio