Mardi Gras Test Tube Shot Glasses. There is a science to the perfect party and these Mardi Gras Test Tube Shot Glasses, will bring you one step closer to a success! Purple, green and yellow colored test tubes make it easier for your guests to move about your party with their drinks! Less spills more Mardi Gras memories! A great way to serve up some fun! Plastic. 1 1/2 oz.