test. The rest of the implementation is identical to using Churnkey in live mode (see Installing Churnkey), including the HMAC signature and its keys.
couponId) only exists on your Stripe live account and not the test account, it cannot be applied to test customers. Rest assured, if test cancelations are working fine, the Stripe integration is performing as it should be, and discounts will function as expected in live mode.
resumes_atfield will automatically be set by ChurnKey depending on the length of the pause selected.