Empire Screen Printing interview questions

I applied for a Graphic Artist position, went to the interview dressed well for an interview. After talking with the owner of the company and showing him my portfolio, he offered me a screen printing position. But I had to go into the shop in my dress clothes and do a full set up and printing of several multiple color shirts to prove my experience and skill. I had no issue with having to prove my skill but I did have a problem with him making me do it in dress clothes. A screen print shop is not always the cleanest place, you do not where good clothes to work when you work in a screen print shop.