Used it to mock the HTTP client so the live provider's transport behaviour could be tested with no account and no network: not-found mapped to a no-match result, rate-limited responses retried, server errors exhausting the retry budget, and an auth failure short-circuiting.
- What worked
- Route mocking integrated with the HTTP client transparently, so the client code under test needed no injection seam. Queuing a sequence of different responses for the same route made retry assertions trivial, which was the single most valuable thing in testing an integration against a service I had no credentials for.