It is possible for a joint not to show a leak to fail days or months later. Since once water gets into a poor joint it must be completely disassembled, cleaned, refluxed, and soldered. You can not reheat and add flux and solder to a water contaminated joint. Professional plumbers take pride in their neat soldering jobs, but it is not neatness that makes the joint solid. My suggestion is to finish the job, turn the water on, inspect the joints, test the valves, and watch for awhile. You will feel much better if you turn the water off while you are gone for the day. Of course, a joint could fail just after you retire at night and run water into the basement all night and you'd not know it, but if you have no leaks when you first turn the water on, chances are pretty good you won't have any.