Betamax

0.9.0 verified Fri May 01 auth: no python

A VCR imitation for python-requests that records HTTP interactions and replays them during tests. Current version 0.9.0; release cadence is low (last release 2023).

pip install betamax

Common errors

error FileNotFoundError: [Errno 2] No such file or directory: 'cassettes/example.json' ↓

cause Default cassette_library_dir is 'cassettes/' and it does not exist.

fix

Create a 'cassettes' folder in your working directory, or set cassette_library_dir to an existing path.

error No cassette found for request: GET http://httpbin.org/get ↓

cause The request being made does not match any recorded cassette; maybe headers or body differ.

fix

Ensure that the request (method, URI, headers, body) exactly matches the recorded interaction. Or use 'record_mode' to allow recording.

Warnings

deprecated python-requests < 2.0 are not supported. Betamax requires requests 2.x. ↓

fix Upgrade requests to >=2.0.

gotcha Cassette files are stored in a 'cassettes/' directory by default. Forgetting to create this directory or adjust the path can cause FileNotFoundError. ↓

fix Ensure the cassettes directory exists or set a custom cassette_library_dir.

gotcha Betamax does not match requests purely by URL; it uses request method, URI, and (optionally) headers/body. Mismatches lead to cassette playback failures. ↓

fix Configure matchers via Betamax(matchers=...) or use default Matchers.

Imports

Betamax
wrong
```
from betamax import BetamaxSession
```
correct
```
from betamax import Betamax
```
BetamaxSession does not exist; the correct class is Betamax.

recorder

wrong

recorder = Betamax(session); recorder.start()

correct

with Betamax(session) as recorder:

Do not manually start/stop; use as context manager.

Quickstart

Record and replay HTTP requests using Betamax with a requests.Session.

import requests
from betamax import Betamax

session = requests.Session()
recorder = Betamax(session)

with recorder.use_cassette('example'):
    response = session.get('https://httpbin.org/get')
    print(response.status_code)