We verify that all necessary directories are created and that all related files, such as .dlls are copied to the appropriate directories. We also ensure that the uninstall works properly by verifying that all of the installed directories and files are removed or correctly modified. Because many of today's applications have multi-user capabilities, tests need to be run to ensure that a product is indeed networkable. We can test your product to make sure it can be run on several network OS environments. Once a product has been tested and fixes have been made to a product, the product needs to be tested again to ensure that all reported bugs have been fixed.
Regression testing is a way to ensure that no new problems have occurred.