allTypesAndFields: Direct serialization of all valid fields for all valid item types
citeProcJSExport: All item types and fields as sent to citeproc-js
itemJSON: Zotero.Item::toJSON serialization of all item types and fields
translatorExport: items as presented to export translators after 4.0.27
translatorExportLegacy: items as presented to export translators before 4.0.27
(does not cover relations, collections, tags, attachments)
Also some support code that was useful here and will probably be
useful for other tests. This is a pretty complicated thing to test, but
it seems to work.
