Test case for xforms:yearMonthDuration datatype 5.2.4.a yearMonthDuration datatype You should see a message "You entered a valid yearMonthDuration" after you enter in a valid yearMonthDuration datatype (i.e. "P100Y1M" for 100 years, 1 month). Length of car lease (yearMonthDuration) You entered a valid yearMonthDuration.