pytest API testing practice: verify ETag cache revalidation

A response without JSON can still be correct. Read the standings once, preserve its ETag, and send that value back in If-None-Match using the same isolated sandbox.

Before you start

Python with pytest and requests installed: python -m pip install pytest requests.
Save the code as test_cache.py and run python -m pytest test_cache.py.
Outbound HTTPS access to funapi.dev.

Compare the original and conditional responses

Use one session and one sandbox identifier for the pair of GET requests. Match the returned ETag exactly, including quotes and its weak-validator prefix.

from uuid import uuid4
import requests

def test_standings_etag_revalidation():
    url = "https://funapi.dev/api/football/v1/standings"
    with requests.Session() as session:
        session.headers.update({"X-Sandbox-ID": str(uuid4())})
        first = session.get(url, timeout=15)
        assert first.status_code == 200
        assert len(first.json()["data"]) > 0
        etag = first.headers.get("ETag")
        assert etag

        cached = session.get(url, headers={"If-None-Match": etag}, timeout=15)
        assert cached.status_code == 304
        assert cached.content == b""
        assert cached.headers["ETag"] == etag

Explain what was saved

The first request transfers the representation. The conditional request revalidates it and receives 304 with no representation body. This exercise checks protocol behavior; it does not claim a measured performance improvement.

Expected result

One passing test that observes 200 followed by 304, an unchanged ETag and an empty second response body.

Common pitfalls

Do not call cached.json(): a 304 has no JSON response body.
Do not strip quotation marks from an ETag.
Do not compare standings to live sports results; the dataset is training data.

Download this practice guide · Download the practice Postman collection

Last updated 16 October 2026