Feature Proposal: Validate EPUB with EPUBCheck upon EPUB export
I'm breaking some of the feature proposals into more granular development tickets, to make prioritizing the next development steps easier. This ticket is one aspect of #254 (see #254 for full context). I'll close #209 (closed) as this replaces it.
Editoria should export an EPUB that is valid and built according to EPUB specifications. EPUBCheck is an open source tool for EPUB validation. This ticket is a development issue for including the results of the EPUBCheck validations of the exported EPUB in real time, to be downloaded along with the exported EPUB itself. This could be a PS job runner job.
Note that this is not the same task as fixing the current EPUBCheck warnings and errors for the current EPUB output. Since the EPUB output is likely to change in the future - removing Viviliostyle-specific features (#321), including metadata (#320), etc), any lingering validation issues should be addressed in those updates (again, see #254).