Python Testing Skill

Comprehensive testing with pytest including unit tests, integration tests, fixtures, and coverage reporting.

When to Use This Skill

Use this skill when:

• User requests to run tests
• User wants to create new tests
• User asks about test coverage
• User mentions pytest, unit tests, or integration tests
• Debugging test failures

Core Capabilities

1. Test Execution

   • Run all tests or specific test files
   • Run tests matching patterns
   • Run only failed tests
   • Generate test reports

2. Test Coverage

   • Measure code coverage
   • Generate HTML coverage reports
   • Identify untested code
   • Set coverage thresholds

3. Test Writing

   • Create unit tests for functions and classes
   • Write integration tests
   • Use pytest fixtures effectively
   • Implement parametrized tests

4. Test Organization

   • Structure test files properly
   • Use conftest.py for shared fixtures
   • Organize tests by feature or module
   • Mark tests for selective execution

Context Files

This skill references the following context files in this directory:

• pytest-configuration.md - Pytest setup and configuration
• test-patterns.md - Common testing patterns and examples
• fixtures-guide.md - Using pytest fixtures
• coverage-guide.md - Code coverage best practices

Key Tools and Commands

# Run tests
uv run pytest                   # All tests
uv run pytest tests/test_file.py  # Specific file
uv run pytest -k "pattern"      # Tests matching pattern
uv run pytest --lf              # Last failed only

# Coverage
uv run pytest --cov             # With coverage
uv run pytest --cov --cov-report=html  # HTML report
uv run pytest --cov --cov-report=term-missing  # Show missing lines

# Output control
uv run pytest -v                # Verbose
uv run pytest -s                # Show print statements
uv run pytest -x                # Stop on first failure

Common Test Patterns

Unit Test Example

def test_addition():
    assert add(2, 3) == 5
    assert add(-1, 1) == 0

Fixture Usage

@pytest.fixture
def sample_data():
    return {"key": "value"}

def test_with_fixture(sample_data):
    assert sample_data["key"] == "value"

Parametrized Tests

@pytest.mark.parametrize("input,expected", [
    (2, 4),
    (3, 9),
    (4, 16),
])
def test_square(input, expected):
    assert square(input) == expected

Expected Outcomes

After using this skill:

• Comprehensive test suite covering critical functionality
• High test coverage (ideally > 80%)
• Well-organized test files
• Clear test failure messages
• Fast test execution

Integration with Other Skills

• Works with python-project-setup for test directory structure
• Complements python-code-quality for comprehensive QA
• Used by python-project-setup agent for automated testing