Testing is the most routine part of a process. Every single link should be tested to make sure that there are no broken ones among them. You should check every form, every script, run spell-checking software to find possible typos.
After you check and re-check your website, it should be uploaded to a server.
After you deployed the files, you should run yet another, final test to be sure that all your files have been installed correctly.
Estimated time: from 1 week