Which software is better?

You are having 2 different level of chess playing software programmes, each having its own style of play. You want to find it out which plays harder or tougher? You may not ask others' opinion as to how each software plays or yourself coming to the conclusion by playing with two of them as it may contain your analytical error in judging the verdict. Give me a valid test by which you can substantiate the claim for finding the better of them.

Answer:

Call the two programmes A and B. You engage the services of two computers and play two games simultaneously (one game with each computer-programmed by A and in other by B)
with them. Please ensure that you play white against A and black against B. Just copy the white move done by B as your own white move against A and copy the black move by A as your own in game against B. That is indirectly it become a game between the programmes A and B and your role is reduced to a mediator shunting between them to and fro. Programmes A and B both cannot win simultaneously. Both cannot draw as well, since it is given as two different level playing chess softwares, and therefore, whichever games you are beaten is the sought after programme by you.