If you know how to sweat a joint there is no need to pressure test. Here are some rules. 1. Good sweats result from nice, clean shinny copper. 2. Use good flux. Not the crap you can buy at WalMart. It burns out too easily especially on tees. Go to a plumbing supply house. 3. MAPP gas is NOT necessary. You will waste your money. Propane is more than adequate and MUCH cheaper. 4. Allow the joint to cool before moving. As you heat the joint evenly, once the proper temp is reached the soider will be drawn into the joint by capillary action. If the joint is overheated and the flux is burned out the soider will not be drawn in and just melt on the copper. The difference is obvious. I have never had a joint fail following the steps outlined.