What testing scenario does not work with test clocks in Stripe?

The option that does not work with test clocks in Stripe is focused on the functionality of account webhooks. Test clocks in Stripe allow developers to simulate the passage of time for testing purposes. This means you can use test clocks to accelerate time and observe how payment processing, subscription lifecycle events, and other time-dependent features behave under various conditions.

However, webhooks are designed to notify your application of events that occur outside the context of your direct interaction, generally initiated by Stripe in real-time. While you may receive webhook notifications related to subscriptions that involve test clocks, the actual mechanism of ensuring that your webhook handling logic (the backend processing of events sent by Stripe) works correctly cannot be tested using test clocks. This is because webhooks are real-time messages sent from Stripe based on actual occurrences and not simulated time advancements.

By using test clocks, you can simulate the effects of various payment timings, customer subscriptions, and limits, but the core functionality related to webhooks—how they are triggered and consumed—does not align with the intended use of test clocks. Therefore, testing the function of account webhooks effectively relies on the actual events occurring rather than any manipulation of time via test clocks.