Can I test PayPal while running on localhost?

We're planning to use nopCommerce to replace something that's not so good (no names, no blame)

I've read the Admin guide to setting up PayPal

/Admin/Payment/ConfigureMethod?systemName=Payments.PayPalStandard

That's fine, I can understand how that would work on a live domain.

But how does it work if I'm trying to test the PayPal sandbox with a development version, running on my local machine, not the real domain IIS server? Our real live domain is still running Paypal with the older software, so I'm reluctant to use our real domain details on the nopCommerce dev config.

Am I missing something simple?

Thanks in advance for any guidance.
Keith