强制提前续订PayPal沙盒订阅

I am testing PayPal's subscription process by using PayPal's sandbox, but the thing is, the minimum period is 1 days, and I want to perform multiple tests until I get everything right, I surely do not need to wait for a period of 1 day to test my code changes.

So there surely should be a way for me to trigger subscription renewal, or some way to work around it.

I've tried to set subscription period to 0.01 days, and PayPal would not accept that. So any suggestions?

Thanks