Testers will need to setup some kind of hardware/software environment in order to run the customer acceptance tests. The environment might require the installation of specific software test tools or the OS might require specific environment settings. Try to replicate as much as possible a typical end-user environment when running the tests. Tests may require setting up multiple environments (when different operating systems are used, for example).

Test environments are not only for testers; it is critical that they are made available to the programmers. Running the acceptance tests is their only way to know whether or not they are through with a story and whether they have broken previous stories or not.