The short answer is, yes, you can loop a whole test. I'm assuming you're working with Keyword tests so, generally, you just select all the test steps within your test, right click, and then select either Make Data Loop or Make Browser Loop depending upon what you are trying to do. That's the easiest way to explain it.
Now, you can also do your standard code loops like "for" loops and "while" loops, but I'm assuming that you're more concerned with looping with a set of parameters of some sort and that's what those two loop modes will do for you.
