Documentation for ResourceSerializer with includes is incorrect

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• Problem/bug report.
• Feature request.
• Request for support. Note: Please try to avoid submitting issues for support requests. Use Gitter instead.

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• I've searched for an existing issue.
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• The feature I'm asking for is compliant with the JSON:API spec.

Description

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Bug reports:

The documentation says that ResourceSerailizer should be able to include resources by doing something like this:

post = Post.find(1)

JSONAPI::ResourceSerializer.new(PostResource,
  include: ['comments'],
).serialize_to_hash(PostResource.new(post, nil))

But when I do this I don't get an included section in the serialized output.

Additionally I don't find any tests in the test suite that demonstrate the documented way of doing it, but I find several tests that seem to achieve includes via much more verbose and laborious methods.

Am I missing something?

Beginne mit dem include-Abschnitt des v0.10-Serializer-Leitfadens und vergleiche dessen Beispiel mit test/unit/serializer/serializer_test.rb um die Zeilen 205–226. Reproduziere den dokumentierten Aufruf von ResourceSerializer und ermittle anschließend, ob die Dokumentation oder das Verhalten des Serializers fehlerhaft ist. Als erledigt gilt die Aufgabe, wenn der dokumentierte include-Workflow korrekt ist und durch einen fokussierten Test abgedeckt wird.