Ryan Taylor's first half effort from outside the box was spilled into the corner of the net and Pope added a second with a classic header a minute after the break, after Law picked out Ellison who crossed from the flank for the big striker to score.
He told the post match media: "It was a great workout and exactly what I wanted.
"We showed our quality in the second half with Pope's goal after being tested in the first half hour. We were gifted a lead but that goal should give Ryan Taylor confidence."
Robins added: "We are starting to see what a player Jason Taylor can be, he put his foot in and won tackles and headers all over the pitch."
Team: Warrington, Lynch, Sharps, Fenton, Green (Joseph 77) Law, Mills (Harrison 75), J Taylor, Ellison (Liddell 62), Pope, R Taylor (Warne 75).
Rotherham face a trip to AFC Emley on Tuesday night in their final friendly of pre-season.