Daniel 1:11-14

But Daniel said to the overseer whom the commander of the officials had appointed over Daniel, Hananiah, Mishael, and Azariah, “Please, test your servants for ten days, and let us be given some vegetables to eat and water to drink. Then let our appearance and the appearance of the young men who eat the king’s finest food be observed and compared by you, and deal with your servants in accordance with what you see.” So the man listened to them in this matter and tested them for ten days.