In ACF2018, introduced a new member function dateObj.format(), which is equivalent to the member function dateObj.dateTimeFormat(). Lucee already supports for member function dateObj.dateTimeFormat() but lucee doesn't support for dateObj.format().
I've added the support for dateObj.format(date,[mask,timezone]) member function for dateTimeFormat(). Modified the test case also.
Pull Request: https://github.com/lucee/Lucee/pull/505