@Test(expected = WrongReferenceAttributeValueException.class)
public void testCheckWithNullPreferredValue() throws Exception {

	System.out.println("testCheckWithNullPreferredValue()");
	Map<String, String> value = new LinkedHashMap<>();
	value.put("example", "example");
	reqAttribute.setValue(value);
	attributeToCheck.setValue(null);
	classInstance.checkAttributeSemantics(session, user, attributeToCheck);
}