What are the best RSpec strategies for testing AI in Rails?

VCR for recordings, WebMock stubs for units, schema/regex asserts over exact matches.

How does VCR make non-deterministic AI tests reliable?

Records one real API response as cassette, replays identically forever — fast, cheap, consistent.

Yes, stub 429s, timeouts, bad JSON — ensure graceful fallbacks every time.

🤖 AI & Machine Learning

You've built the AI chat. It wows in dev. Then prod eats it alive. Non-deterministic outputs strike again.

theAIcatchup Apr 11, 2026 3 min read

VCR turns non-deterministic AI APIs into fast, repeatable tests with one real call. 𝕏
Stub 70% of tests for speed; use patterns and schemas, not exact matches. 𝕏
Error handling stubs prevent prod crashes — rate limits, timeouts, bad JSON. 𝕏

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#OpenAI RSpec #OpenAI Rails #OpenAI stubs #RSpec VCR #RSpec non-deterministic #Rails AI testing #VCR gem #non-deterministic tests

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Originally reported by Dev.to