Builds test suites for Stripe recurring-billing flows: trial-to-paid conversion, proration on plan upgrade and downgrade, dunning on failed renewal, cancel and reactivation, and the full subscription webhook event matrix (invoice.payment_failed, customer.subscription.updated, customer.subscription.deleted, invoice.paid). Uses Stripe Billing test clocks (POST /v1/test_helpers/test_clocks) to time-travel through billing cycles without calendar delay. Distinct from stripe-test-cards-and-webhooks (one-time PaymentIntents) and payment-webhook-replay (idempotency + replay robustness). Does not cover single-event CLI replay or handler idempotency testing (see payment-webhook-replay for those). Use when authoring tests for subscription or recurring-billing integrations.