I would like to test the address before I trust it so I know it's really a valid key. But then I expose the public key and then I doesn't feel 100% secure because of that. This test shouldn't be needed if it was included in Armory because I trust that Amory doesn't fuck things up like I might do.
If you have the correct number of bits, there is no such thing as an "invalid key".
But calculating the corresponding bitcoin address by hand might be error prone, and it would be really nasty transferring funds to a wrongly calculated address.
But then, just import the private key in an armory wallet, check that it gives a bitcoin address, and then use it.