Fixed test for supported audio codecs

Ignore-this: 9c982ebd10b65dbb78370491440805c1

darcs-hash:20121214110239-b22ec-7da43cc391be57eae41118c3531cfe4d0f3c0dbf
Avoid having duplicate code

Ignore-this: 9112c2cd29828f891059f1433acbd949

darcs-hash:20121214123105-b22ec-e67ff01423837f1b70cf61dfd322e77a1629438c