Just got these, and apparently the Virtual Terminal (VT) account needs to be in Test Mode for these test cc's to work - which I could have sworn wasn't the case aways back.
VISA - 4111-1111-1111-1111
MasterCard - 5499-7400-0000-0057
American Express - 3714-4963-5392-376
Discover - 6011-0009-9302-6909
(""Expiration Date: Any future date will work"")