How to test the battery pack before replacing it?

I have a dead Surface Pro3, presumably with a defective battery pack. After many months of looking at it I took the plunge, broke through the screen and have the battery tail with its connector free. The main connector tabs show zero volts but Im not sure if this indicated a dead cell or that I am not enabling a switch within the battery management scheme which is part of the battery pack.

Can anyone tell me if the battery tail should be at 7.5V standalone, ie how do I test the battery pack before trying to replace it?