How do you move an UI testing for a web site project to a web application project?

I was not able to do unit testing for our existing web site project. I converted the web site project to a web application project. I did some unit testing and changes on the converted web application project. However, my co-worker was doing UI testing on the web site project.  We need put UI testing and unit testing to the web application project. Is it possible to move the UI testing code that my co-worker did to the web application project I am working? If so, how do you do it? Thank you for your help.
Li Ai Shen
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