-$m->form_name('TicketModifyAll');
-$m->field('Due_Date' => "2016-01-01 00:00:00");
-$m->click('SubmitTicket');
-$m->text_contains("Due: (Fri Jan 01 00:00:00 2016)", 'due date successfully updated');
+for my $unset ("0", "-", " ") {
+ $m->form_name('TicketModifyAll');
+ $m->field('Due_Date' => "2016-01-01 00:00:00");
+ $m->click('SubmitTicket');
+ $m->text_contains("Due: (Fri Jan 01 00:00:00 2016)", 'due date successfully updated');
+
+ $m->form_name('TicketModifyAll');
+ $m->field('Due_Date' => $unset);
+ $m->click('SubmitTicket');
+ $m->text_contains("Due: (Not set)", "due date successfully cleared with '$unset'");
+ $m->warning_like(qr/Couldn't parse date '-'/) if $unset eq "-";
+}