Not specifically an FPGA question, but does anyone know of any free
JTAG testing software?

I've got (or will have) lots of assembled boards to test, and I'm
thinking about using JTAG. The problem is, the software needs to work
out for itself what the netlist is from a known good board. I can buy
software to do this, but it'll double the cost of the assembled board.

Cheers

RT