The project I´m working on needs to auth its users against AD, and as a fallback check against its own user base. Now I need to test it outside the production environment.
What is the best method to setup a Active Directory test environment? Currently I´m downloading a Windows 2003 Virtual PC image, and planning a VMWare virtual LAN.
Is there any problem in that approach?
You should think about multi-domain and multi-forest environments, as well as just having multiple domain controllers in the domain you're authenticating against. You're going to need more than a single VM to do that.
Is this environment suppose to simulate as many ActiveDirectory installations as possible, or is it to just test that authentication works against a DC?
At a minimum, you will want to setup two Domain Controllers, a Primary and a Secondary. You will want to also setup accounts with a variety of account states (password expired, account expired, account lockout, etc).
Some other issues to think about:
Is your domain running as a Win2000 functional Domain? or a Windows 2003 functional Domain? If you have multiple domains, will you support Universal Group membership? If you have multiple forrests, will you support Cross-Forest Trust relationships?