data.put(UserField.kUserType, UserType.kVip);
data.put(UserField.kDaysServed, 30);
List<Slip> slips = new ArrayList<Slip>();
slips.add(new Slip(SlipType.kShortMessage, new LocalDateTime(), 1));
data.put(UserField.kSlips, slips);
UserMonthUsage usage = new UserMonthUsage(1, data);
assertEquals(Money.get(60, 10), calculator.calculate(usage));
}