Q5: Approach to automated testing in Python: - Python & FastAPI

In Simple Words:

pytest with pytest-asyncio for async tests.
Wrap tests in transactional rollbacks so every test runs in an isolated nested transaction that rolls back on teardown (fast, clean, and avoids database truncation).
Mock external HTTP APIs using respx and run real PostgreSQL/Redis instances in CI with Testcontainers.

python

import pytest
from httpx import AsyncClient, ASGITransport
from app.main import app

@pytest.mark.asyncio
async def test_create_user(db_session):
    async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as ac:
        response = await ac.post("/api/v1/users", json={"email": "test@example.com", "full_name": "Test User", "age": 28})
        assert response.status_code == 201
        assert response.json()["user"]["email"] == "test@example.com"