@Test
public void evaluateFieldRef(){

	FieldName name = FieldName.create("x");
	FieldRef fieldRef = new FieldRef(name);
	assertEquals("3", evaluate(fieldRef, name, "3"));
	assertEquals(null, evaluate(fieldRef, name, null));
	fieldRef.setMapMissingTo("Missing");
	assertEquals("Missing", evaluate(fieldRef, name, null));
}