Fix for missing audioitem.linein DIDL data structure

[tagdara]

I've recently started using the Line-in on my Sonos Connect, and Soco crashes with an unknown data structure type. It claims to be a subset of AudioItem, so I simply copied over that object and tacked on the linein designator.

This is another case where SoCo should probably just roll-up to the parent object when encountering subclasses rather than maintaining a hardline on DIDL compliance since that is clearly not a priority for Sonos (see my previous comments around lack of ProtocolID and other stuff being addressed by quirks).

But since there are fewer examples of the . subclassing than # subclassing and line-in is a common feature across several Sonos devices, it makes sense to target this one directly.

[coveralls]

Coverage increased (+0.08%) to 57.507% when pulling 0b49c01 on tagdara:master into e23a162 on SoCo:master.

[KennethNielsen]

@tagdera I think maybe we discussed this before. I care mainly about DIDL compliance due to it being easier to maintain, but since these kind of problem are quite a few of the ones we receive I have been toying with the idea and reducing the data_structures implementation to just the ones in the spec and then generating the rest of them on request and flat extensions on their super class.

It takes a little while, because I want to setup tests for all the out of spec classes that I will remove to ensure against regressions. If you want to give it a jab, let me know. Otherwise I will proceed with it.

[KennethNielsen]

@tagdara I've tried to address this with #713. Please test and review. BTW in our code there was references to .# syntax for subclasses being observed, compared to the normal . syntax, but have you ever seen one where just # was used?

[tagdara]

There was at least one case where I saw a # being used by itself from Spotify, but perhaps not in exactly the same way. I have this in my local monkeypatched SoCo that I have been testing before I submitted another PR. I believe it was the Spotify Daily Mixes that were causing this issue for me.

class DidlPlaylistContainerPlaylistItem(DidlPlaylistContainer):

    # Cheese created by Spotify errors on 2/8
    """Class that represents a Sonos tracklist."""
    item_class = 'object.container.playlistContainer#playlistItem'

[KennethNielsen]

Thanks.

I merged #713 which now hopefully takes care of all these vendor specific classes, so I will close this one. Let me know of you still have issues.