@Test
public void testFindSuccessfulByTaxCalculation_returnsNullWhenNoCall() {

    TaxCalculation march = new TaxCalculationTestBuilder()
            .withEmployee(employee)
            .withMonth(3)
            .withTax(10.0)
            .build();
    ;
    taxCalculationRepository.save(march);
    TaxWebserviceCallResult successfulByTaxCalculation = taxWebserviceCallResultRepository.findSuccessfulByTaxCalculation(march);
    assertThat(successfulByTaxCalculation).isNull();
}