Adding/modifying tomcat web root directory

I create a lot of test cases to test features/enhancements/bugs so I can submit forum posts with the minimum code necessary. Right now, my test directory is located under smartClientSDK in the distribution. When I download a new version, I copy this folder.

many times I am editing test cases and have to copy from one distribution to another. How can I configure Tomcat to pint to an additional folder on my local filesystem, so I can have a centralized folder of test cases that all of my distributions would use?