changedRelationships does not track first hasOne

[aars]

Because of this check in ref.previous an hasOne relationship that was previously empty will not show up in changedAttributes since ref.previous is null.

https://github.com/pixelhandler/ember-jsonapi-resources/blob/master/addon/models/resource.js#L373

[aars]

I think that should be return !!ref.changed || (ref.removals && ref.removals.length) || (ref.added && ref.added.length);

[pixelhandler]

@aars so change !!ref.previous to !!ref.changed. Is there anything in this test that appears to not test your use case? https://github.com/pixelhandler/ember-jsonapi-resources/blob/master/tests/unit/models/resource-test.js#L305-L321

[aars]

@pixelhandler I'm sorry, that was some horrible issue-reporting by me.

Yes. That test does not check if changedRelationships will contain the author after that first addRelationship. It does not currently.

Proof and fix in this PR

[pixelhandler]

@aars released 1.5.2 - https://github.com/pixelhandler/ember-jsonapi-resources/releases