I know, but if I give the publisher my game to test out, can't they just publish it right off the bat with no deal if I don't get the copyright stuff out of the way?
I have known one or two developers over the last ten years who got ripped off by dodgy publishers but they were small crap publishers who were about to go bust and a bit of research would have shown that they weren't people to do business with. Apart from that publishers simply don't steal games - it isn't worth the hassle and the bad rep they would get would stop future devs working with them. Besides which they don't need to rip you off by breaking the law when they can do it legally by getting you to sign a complex contract that ends up giving them all the benefit from the sales of your game.
Publishers stealing your game isn't going to be a problem. Your first problem will be making a great game and then getting them to even look at it.