Daniel 1:11-14

Then Daniel said to the steward whom the chief of the eunuchs had assigned over Daniel, Hananiah, Mishael, and Azariah, “Test your servants for ten days; let us be given vegetables to eat and water to drink. Then let our appearance and the appearance of the youths who eat the king’s food be observed by you, and deal with your servants according to what you see.” So he listened to them in this matter, and tested them for ten days.