1. A computer-readable medium having executable instructions for evaluating a test policy, the executable instructions, when executed by a computer, causing the computer to perform acts comprising: creating a test policy; associating said test policy with a scope; receiving a request to access a resource that is within said scope; evaluating said request under said test policy to determine whether said request is to be allowed or denied under said test policy; evaluating said request under an effective policy that is associated with said scope to determine whether said request is to be allowed or denied under said effective policy; making a determination of whether to allow or to deny access to said resource under said effective policy but not under said test policy, said request being evaluated by one access control system under both said effective policy and said test policy even though said test policy is not used to determine whether to allow or to deny access to said resource; allowing or denying access to said resource based on said determination; and logging differences in evaluation of said request between said test policy and said effective policy.