Last month, in a series of entries, I laid out the case for an effort — inspired by the RSS/Atom feed validator — to create a similar suite of tests and tools for iCalendar feeds.

I’m delighted to report that two developers of libraries that support iCalendar are collaborating to do just that. Ben Fortuna is the author of iCal4j, which powers the best currently-available online iCalendar validator. And Doug Day is the author of DDay.iCal, a C# iCalendar library. Both iCal4j and DDay.iCal are open source projects.

They’re collaborating, at icalvalid.wikidot.com, on a platform-neutral suite of tests that can serve as foundation for a more robust iCalendar validation service.

As Sam Ruby points out:

For each of the red entries on that page, somebody needs to identify what should be tested for, and for each test identify a short message, an explanation, and a solution. Identifying real issues that prevent real feeds from being consumed by real consumers and describing the issue in terms that makes sense to the producer is what most would call value.

We’ve made a start on the wiki. As I proceed with my calendar aggregation project, I’ll continue to document the validation issues I run into. Meanwhile, in the spirit of loosly-coupled collaboration, please feel free to attach the tag icalvalid to any blog posting, forum message, or other online item that discusses iCalendar feeds that fail to validate, explores reasons why, and recommends solutions.