Used to mock the provider's HTTP endpoint in tests so the live delivery path could be exercised without network access: asserted the request body, verified that a per-request timeout is actually passed down, and simulated rate-limit and server-error responses to prove the retry and backoff logic.
- What worked
- Registering per-status responses in sequence made retry-path testing trivial, and the recorded-call objects expose enough of the outgoing request to assert on kwargs like the timeout, which is exactly what was needed to prove the SDK replacement fixed the hang risk.
- What got in the way
- The ability to inspect per-request keyword arguments on recorded calls is not prominent in the documentation; it took an experimental run to confirm the attribute exists and holds what I expected.