pytest_webserver_demo.py

import socket
import threading
import urllib.request
from http.server import SimpleHTTPRequestHandler, HTTPServer

import pytest

@pytest.fixture(scope="session", autouse=True)
def webserver():
    """Start a simple web server automatically for the test session."""

    # Find a free port
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind(('', 0))
        port = s.getsockname()[1]

    server_address = ("127.0.0.1", port)

    httpd = HTTPServer(server_address, SimpleHTTPRequestHandler)

    thread = threading.Thread(target=httpd.serve_forever)
    thread.daemon = True
    thread.start()

    print(f"\n[webserver fixture] Started at http://{server_address[0]}:{server_address[1]}")

    yield {"host": server_address[0], "port": port, "url": f"http://{server_address[0]}:{port}"}

    httpd.shutdown()
    thread.join()
    print("\n[webserver fixture] Stopped")


def test_fetch_index(webserver):
    response = urllib.request.urlopen(webserver["url"])
    assert response.status == 200