How is Durock cement board finished to match drywall when the cement board isn't covered with tile?

I have a wall mount sink to install that specifies that it should have cement board on the wall behind it. I don't plan to tile that area of the wall - certainly not the the part of the wall that is under the sink. What should go over the cement board so it roughly matches the finish on the drywall in the rest of the room? - joint compound?