Pytest Builder

Build comprehensive test suites for Python projects using pytest, with specialized support for FastAPI, async code, and SQLModel/SQLAlchemy.

Quick Start

Generate test file from existing code:

bash

python3 scripts/generate_test.py myapp/users.py --type unit

Setup pytest configuration:

bash

python3 scripts/setup_pytest_config.py . --template fastapi

Generate fixtures:

bash

python3 scripts/generate_fixtures.py --fixtures database api_client --output tests/conftest.py

Core Capabilities

1. Generate Test Files

Create test files from existing Python code with proper structure:

bash

# Basic unit tests
python3 scripts/generate_test.py myapp/module.py

# FastAPI integration tests
python3 scripts/generate_test.py myapp/routers/users.py --type integration

# Async tests
python3 scripts/generate_test.py myapp/async_service.py --async

The script extracts functions and classes from your code and generates test stubs.

2. Setup Pytest Configuration

Initialize pytest with recommended settings:

bash

# Basic Python project
python3 scripts/setup_pytest_config.py . --template basic

# FastAPI project
python3 scripts/setup_pytest_config.py . --template fastapi

# Async project
python3 scripts/setup_pytest_config.py . --template async

This creates:

```
pytest.ini
```
with optimal configuration
```
tests/
```
directory structure (unit/, integration/, test_data/)
```
tests/conftest.py
```
with common fixtures

3. Generate Fixtures

Create reusable fixtures for common testing scenarios:

bash

# List available fixtures
python3 scripts/generate_fixtures.py --list

# Generate specific fixtures
python3 scripts/generate_fixtures.py --fixtures database api_client auth_token

# Generate all fixtures
python3 scripts/generate_fixtures.py --fixtures all

# Append to existing conftest.py
python3 scripts/generate_fixtures.py --fixtures mock_external_api --append

Available fixture types:

```
database
```
- SQLModel in-memory database fixtures
```
async_database
```
- Async SQLAlchemy database fixtures
```
api_client
```
- FastAPI TestClient fixtures
```
async_client
```
- httpx AsyncClient fixtures
```
mock_external_api
```
- Mock external API calls
```
temp_files
```
- Temporary files and directories
```
sample_user
```
- Sample user model fixtures
```
auth_token
```
- Authentication token fixtures

Testing Patterns

FastAPI Testing

For detailed FastAPI testing patterns, see references/fastapi-testing.md:

TestClient usage
Async endpoint testing with httpx
Dependency overrides
Authentication testing
Response validation
Error handling

Quick example:

python

from fastapi.testclient import TestClient
from myapp.main import app

client = TestClient(app)

def test_read_items():
    response = client.get("/items/")
    assert response.status_code == 200
    assert isinstance(response.json(), list)

Async Testing

For async testing patterns, see references/async-testing.md:

pytest-asyncio setup
Async fixtures
Testing async endpoints
Concurrent operations
Error handling

Quick example:

python

import pytest
from httpx import AsyncClient

@pytest.mark.asyncio
async def test_async_endpoint():
    async with AsyncClient(app=app, base_url="http://test") as ac:
        response = await ac.get("/items/")
    assert response.status_code == 200

Database Testing

For database testing patterns, see references/database-testing.md:

In-memory database setup
Transaction rollback patterns
Testing CRUD operations
Testing relationships
Query testing

Quick example:

python

import pytest
from sqlmodel import Session, create_engine, SQLModel
from sqlmodel.pool import StaticPool

@pytest.fixture(name="session")
def session_fixture():
    engine = create_engine(
        "sqlite:///:memory:",
        connect_args={"check_same_thread": False},
        poolclass=StaticPool,
    )
    SQLModel.metadata.create_all(engine)
    with Session(engine) as session:
        yield session

Fixtures Library

For comprehensive fixture patterns, see references/fixtures-library.md:

Fixture scopes (function, module, session, class)
Database fixtures
API client fixtures
Authentication fixtures
Mock fixtures
Parametrized fixtures
Fixture composition

Common Workflows

Setting Up Tests for a New FastAPI Project

Initialize pytest configuration:

bash

python3 scripts/setup_pytest_config.py . --template fastapi

Generate fixtures:

bash

python3 scripts/generate_fixtures.py --fixtures database api_client sample_user

Generate test files:

bash

python3 scripts/generate_test.py myapp/routers/items.py --type integration

Run tests:

bash

pytest

Adding Tests to Existing Module

Generate test file:

bash

python3 scripts/generate_test.py myapp/services/auth.py --output tests/unit/test_auth.py

Review and customize generated tests
Add specific fixtures if needed:

bash

python3 scripts/generate_fixtures.py --fixtures auth_token --append

Testing Async Database Operations

Generate async fixtures:

bash

python3 scripts/generate_fixtures.py --fixtures async_database async_client

Create async tests following patterns in references/async-testing.md
Run with pytest-asyncio:

bash

pytest --asyncio-mode=auto

Best Practices

Test Organization:

Keep tests isolated and independent

Use descriptive test names:

test_<feature>_<scenario>_<expected_outcome>

Test both happy paths and edge cases
Organize tests:
```
tests/unit/
```
for unit tests,
```
tests/integration/
```
for integration tests

Fixtures:

Use appropriate scopes (function, module, session)
Keep fixtures focused and reusable
Use fixture composition for complex setups
Clean up resources in fixtures using yield

FastAPI Testing:

Use dependency overrides for testing
Test authentication and authorization
Validate response schemas
Test error handling

Database Testing:

Use in-memory databases for speed
Isolate tests with transactions or fresh databases
Test relationships and cascades
Avoid N+1 query problems

Async Testing:

Use pytest-asyncio for async tests
Test concurrent operations
Handle timeouts and cancellations
Test async context managers

Assets

Template files for quick project setup:

```
assets/pytest.ini
```
- Recommended pytest configuration
```
assets/conftest_basic.py
```
- Basic conftest.py template
```
assets/conftest_fastapi.py
```
- FastAPI-specific conftest.py
```
assets/test_template.py
```
- Example test file with common patterns

Copy these templates to your project as starting points.

Installation Requirements

bash

# Basic pytest
pip install pytest pytest-cov

# Async support
pip install pytest-asyncio

# FastAPI testing
pip install httpx

# Database testing
pip install sqlmodel

pytest-builder

NPX Install

Tags

SKILL.md Content

Pytest Builder

Quick Start

Core Capabilities

1. Generate Test Files

2. Setup Pytest Configuration

3. Generate Fixtures

Testing Patterns

FastAPI Testing

Async Testing

Database Testing

Fixtures Library

Common Workflows

Setting Up Tests for a New FastAPI Project

Adding Tests to Existing Module

Testing Async Database Operations

Best Practices

Assets

Installation Requirements