Upload a drupal site to the server to test I have finished the drupal website on my localhost. I want to upload everything to the server, but only to test before officially launching it. Is there a way that I can keep my current non-drupal website running normally, but also upload this drupal site and test it at the same time?

If I create a new directory on the root, say '/drupal_test, and put everything there for now, will that be a problem when I copy everything to the root later? Or is there any standard drupal way to do it?

Thanks!
I suggest you instead use any other unused domain. In that case robots.txt, .httaccess will work normally. And also there is risk of Googlebot indexing this content.

Just add "Disallow:/" in the robots.txt as a first rule.