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+---
+name: pytest
+description: |
+  Python testing with pytest framework for unit, integration, and API tests.
+  Use when: (1) Writing test cases for Python code, (2) Setting up pytest fixtures,
+  (3) Testing async functions with pytest-asyncio, (4) Mocking dependencies,
+  (5) Parameterizing tests, (6) Testing FastAPI/Flask endpoints, (7) Setting up test coverage,
+  (8) Creating test factories with factory_boy, (9) Configuring CI/CD test pipelines.
+---
+
+# Pytest Testing Skill
+
+Comprehensive testing patterns for Python applications using pytest.
+
+## Quick Reference
+
+| Feature | Reference File |
+|---------|----------------|
+| Fixtures, conftest, scopes | [references/fixtures.md](references/fixtures.md) |
+| Async testing, pytest-asyncio | [references/async-testing.md](references/async-testing.md) |
+| Mocking, patching, spies | [references/mocking.md](references/mocking.md) |
+| FastAPI/Flask endpoint testing | [references/api-testing.md](references/api-testing.md) |
+
+## Dependencies
+
+```toml
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.0.0",
+    "pytest-asyncio>=0.24.0",
+    "pytest-cov>=4.1.0",
+    "httpx>=0.28.0",           # Async HTTP client for API tests
+    "factory-boy>=3.3.0",      # Test factories
+    "faker>=33.0.0",           # Fake data generation
+]
+```
+
+## Configuration
+
+### pyproject.toml
+
+```toml
+[tool.pytest.ini_options]
+asyncio_mode = "auto"
+testpaths = ["tests"]
+python_files = ["test_*.py"]
+python_functions = ["test_*"]
+addopts = "-v --tb=short"
+filterwarnings = ["ignore::DeprecationWarning"]
+
+[tool.coverage.run]
+source = ["app"]
+omit = ["*/tests/*", "*/__init__.py"]
+```
+
+## Basic Test Structure
+
+```python
+import pytest
+
+# Simple test function
+def test_addition():
+    assert 1 + 1 == 2
+
+# Test class (group related tests)
+class TestCalculator:
+    def test_add(self):
+        assert add(2, 3) == 5
+
+    def test_subtract(self):
+        assert subtract(5, 3) == 2
+
+# Expected exceptions
+def test_division_by_zero():
+    with pytest.raises(ZeroDivisionError):
+        divide(1, 0)
+
+# Parametrized tests
+@pytest.mark.parametrize("input,expected", [
+    (1, 1),
+    (2, 4),
+    (3, 9),
+])
+def test_square(input, expected):
+    assert square(input) == expected
+```
+
+## Fixtures
+
+```python
+import pytest
+
+@pytest.fixture
+def sample_user():
+    return {"name": "John", "email": "john@example.com"}
+
+@pytest.fixture
+def db_connection():
+    conn = create_connection()
+    yield conn       # Test runs here
+    conn.close()     # Cleanup after test
+
+# Use fixture in test
+def test_user_name(sample_user):
+    assert sample_user["name"] == "John"
+```
+
+## Async Testing
+
+```python
+import pytest
+
+@pytest.mark.asyncio
+async def test_async_function():
+    result = await async_operation()
+    assert result == "success"
+
+@pytest.fixture
+async def async_client():
+    async with AsyncClient() as client:
+        yield client
+```
+
+## Mocking
+
+```python
+from unittest.mock import patch, MagicMock, AsyncMock
+
+def test_with_mock():
+    with patch("module.external_api") as mock_api:
+        mock_api.return_value = {"data": "mocked"}
+        result = function_using_api()
+        assert result["data"] == "mocked"
+        mock_api.assert_called_once()
+
+# Async mock
+@pytest.mark.asyncio
+async def test_async_mock():
+    with patch("module.async_call", new_callable=AsyncMock) as mock:
+        mock.return_value = "result"
+        result = await function_with_async_call()
+        assert result == "result"
+```
+
+## Running Tests
+
+```bash
+# Run all tests
+pytest
+
+# Verbose output
+pytest -v
+
+# Run specific file
+pytest tests/test_users.py
+
+# Run specific test
+pytest tests/test_users.py::test_create_user
+
+# Run with coverage
+pytest --cov=app --cov-report=term-missing
+
+# Stop on first failure
+pytest -x
+
+# Run last failed tests
+pytest --lf
+
+# Run tests matching pattern
+pytest -k "user and not delete"
+```
+
+## Project Structure
+
+```
+project/
+├── app/
+│   ├── __init__.py
+│   ├── main.py
+│   └── services/
+├── tests/
+│   ├── __init__.py
+│   ├── conftest.py      # Shared fixtures
+│   ├── test_main.py
+│   └── test_services/
+└── pyproject.toml
+```