Another Reddit user also spotted an article on the Microsoft retail partner training portal which also teased that the app will be coming to Xbox saying "This week, Microsoft announced huge news that impacts more than one of those devices". But it seems that Spotify is preparing to release an app for the Xbox One in the near future.
It looks like you might be listening to your Spotify library on your Xbox One before long. Those sources say that the app is now undergoing internal testing, which meshes nicely with what we say from Major Nelson. Of course, we hope it's the former, but that would likely represent a significant engineering effort Spotify may not be ready to jump into. Oh, you wanted more games huh? The app also seamlessly integrates into the PlayStation 4's quick menu overlay, which we expect would function similarly on the Xbox One.
For over two years, the only way to use Spotify on game consoles was through PlayStation 3 and 4.
Microsoft is said to be planning a number of dashboard enhancements and features over the coming months prior to the launch of the Xbox One X console.
Stay tuned for additional details as they become available.