I'm not sure I understand the problem - are you saying that you want to develop a test suite specifically to test this one new web app? Others have already covered suggestions for this.

Or would a generic test suite suffice, that would verify that your webserver is up and running, and verify that a web app can interact with a database? If this is the case, then you could create a new database, and a new "testing" app to make sure the webserver is functioning properly and to make sure the web app can interact with the testing database.

HTH.