@Test
public void testGetSuccessSum() throws Exception {

    when(taxCalculationRepository.getSuccessSum(TEST_YEAR, TEST_MONTH)).thenReturn(MONEY_100Euro);
    double successSum = sumOfTaxes.getSuccessSum(TEST_YEAR, TEST_MONTH);
    verify(taxCalculationRepository).getSuccessSum(TEST_YEAR, TEST_MONTH);
    assertTrue(successSum == MONEY_100Euro.getAmount().doubleValue());
}