pytest-setup

Skill: Test Framework Setup (pytest)

When to Use This Skill

This skill activates when you need to:

• Set up pytest from scratch in a Python project
• Add coverage reporting to existing tests
• Configure watch mode for test-driven development
• Fix broken pytest configurations

Prerequisites

Check if testing is already configured:

• Look for {{test_dirs}} (e.g., tests/, test/, or __tests__/)
• Check for pytest in requirements.txt, pyproject.toml, or Pipfile
• Verify {{test_command}} exists in project configuration

If already configured: This skill provides configuration improvements and troubleshooting.

Step-by-Step Workflow

Step 1: Install pytest and Extensions

If using pip (requirements.txt):

pip install pytest pytest-cov pytest-watch

Add to requirements.txt or requirements-dev.txt:

pytest>=7.4.0
pytest-cov>=4.1.0
pytest-watch>=4.2.0

If using Poetry:

poetry add --group dev pytest pytest-cov pytest-watch

If using Pipenv:

pipenv install --dev pytest pytest-cov pytest-watch

If using conda:

conda install pytest pytest-cov
pip install pytest-watch

Step 2: Create Test Directory Structure

# Create main test directory
mkdir -p tests

# Create __init__.py to make it a package
touch tests/__init__.py

# Create conftest.py for shared fixtures
touch tests/conftest.py

# Create your first test file
touch tests/test_example.py

Add a sample test to tests/test_example.py:

def test_basic_example():
    """Basic example test to verify pytest is working."""
    assert 1 + 1 == 2
    
def test_string_operations():
    """Test string operations."""
    assert "hello".upper() == "HELLO"

Step 3: Add pytest Configuration

Option A: pytest.ini (Recommended)

Create pytest.ini in project root:

[pytest]
testpaths = tests
python_files = test_*.py *_test.py
python_classes = Test*
python_functions = test_*
addopts = 
    -v
    --strict-markers
    --cov=src
    --cov-report=html
    --cov-report=term-missing
    --cov-report=xml
markers =
    slow: marks tests as slow (deselect with '-m "not slow"')
    integration: marks tests as integration tests