program volatile_doctest use stringifor_string_t type(string) :: astring logical :: test_passed(1) astring = 'the Quick Brown fox Jumps over the Lazy Dog.' test_passed(1) = astring%snakecase()//''=='the_quick_brown_fox_jumps_over_the_lazy_dog.' print '(L1)', all(test_passed) endprogram volatile_doctest