What is a test pressing?

Just purchased a test pressing of Waltz for Debby from Acoustic Sounds. Is this supposed to sound better than the regular l.p.?
Yes. I have that Test Pressing as well. Test Pressing's were the first off the press and if they are the test pressing of the master that was used, then it will definitely sound better (at least in my experience). In general there about 10 to 20 test pressings per master. Test pressing are just for the purpose of seeing the pressing is going to be good. Sometimes, there are problems in which case a new master must be made, and the prior test pressings should be destroyed.
I have a number of test pressings and what I find is that Rives is correct. However, I have a few which make me wonder whether the "should" in his last sentence is rather loosely followed! :-)
Test pressings might also have tracks located differently from the original album.