Question: Test Weapon Completion Status

How is Bungie.net determining how a Test Weapon has been "tested" based on the data being returned from the APIs? For reference you can inspect a test weapon at the Gunsmith with either [url=http://bungienetplatform.wikia.com/wiki/GetAdvisorsForCurrentCharacter]GetAdvisorsForCurrentCharacter[/url] or [url=http://bungienetplatform.wikia.com/wiki/GetVendorItemDetailForCurrentCharacter]GetVendorItemDetailForCurrentCharacter[/url], both are private endpoints so I can understand if this question goes beyond what is supported. Right now there are a quite a few unlockflag-type attributes in these structures, my favourite has been the one that makes use of the failureIndexes (as seen on collection items) however they don't seem to be returning any indexes on test weapons I know I have tested. The Gunsmith vendor definition has failureStrings so I'm just wondering if I've missed something or is this a bug?