public void assertVisitWithoutNowWorks(String expression) throws ParseException {
        DocumentSelector selector = new DocumentSelector(expression);
        NowCheckVisitor visitor = new NowCheckVisitor();
        selector.visit(visitor);
        assertFalse(visitor.requiresConversion());
    }
@author Simon Thoresen Hult
@author bratseth
document/src/test/java/com/yahoo/document/select/DocumentSelectorTestCase.java