Abstract: A beverage test apparatus, including a container, for containing beverage to be tested; an opening disposed on the container, the opening being covered by a one-way valve, for allowing entrance of the beverage into the container, and for disallowing exit therefrom, and a chromatography substance contained in the container, for changing a color of the chromatography substance upon presence of a certain ingredient, thereby a portion of beverage poured into the cup enters the container and is tested by the chromatography substance, and thereby the one-way valve disallows access of the chromatography substance to the beverage being drunk by the user, where the beverage test apparatus may further include a sticker attached to the container, for sticking the container to the drinking cup.