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

	System.out.println("testCheckAlreadyOccupiedValue()");
	when(session.getPerunBl().getUsersManagerBl().getUsersByAttribute(session, attributeToCheck)).thenReturn(Arrays.asList(user, secondUser));
	classInstance.checkAttributeSemantics(session, user, attributeToCheck);
}