notMandatoryMissingRequest.addParameter("testForm.myDateTime", (String) null);
notMandatoryMissingRequest.addParameter("testForm.hierarchyTest.myTextarea", "blah");
notMandatoryMissingRequest.addParameter("testForm.hierarchyTest.mySelect", "2");
// create helper
ConstraintGroupHelper groupHelper = new ConstraintGroupHelper();
testForm.getElement("myDateTime").setConstraint(
groupHelper.createGroupedConstraint(new NotEmptyConstraint(), "active"));
StandardServletInputData input = new StandardServletInputData(notMandatoryMissingRequest);
input.pushScope("testForm");
testForm._getWidget().update(input);
groupHelper.setActiveGroup("active");
assertTrue("Test form must not be valid after reading from request", !testForm.convertAndValidate());
}