Is there a way to write a selenium script for something that will take a long time?

Background

I have a site that allows for companies to advertise. Part of the procedure is picking a date to start and finish the advertising. This means that the advertising should be inactive until its date comes up.

Selenium

I'm using selenium tests with Testng, Maven and Jenkins to run headless tests on my server. These tests should cover every area of the site, I have just reached the advertising but cant see how I will test the advertising.

My test needs to create some advertising and see if it comes on-line the next day, but I cant see how to test that with selenium.

I can create the advert with my script no problem but can't see if it comes on-line tomorrow without something stupid like a day long thread sleep.

Question

Is this kind of test possible with a workaround? Or is this something Selenium just cant handle? Or perhaps I am going about this the wrong way?