A list that can be used for interoperability tests would be great, even across languages. For example, Perl has DateTime::Format::Natural that provides this fun

A list that can be used for interoperability tests would be great, even across languages. For example, Perl has DateTime::Format::Natural that provides this functionality. There's a list of supported inputs at http://search.cpan.org/dist/DateTime-Format-Natural/lib/DateTime/Format/Natural/Lang/EN.pm http://search.cpan.org/dist/DateTime-Format-Natural/lib/Date... . I guess such a list of test-cases could simply be a JSON file containing the input strings plus an output specification. The options for output would only be explicit datetimes, datetimes relative to the now, or timespans.