### Question:
BillingApiService { public List<BillingChartInfo> getBillingChartInfoPaginated(final BillingChartRequest request) { return billingManager.getBillingChartInfoPaginated(request); }  List<BillingChartInfo> getBillingChartInfo(final BillingChartRequest request); List<BillingChartInfo> getBillingChartInfoPaginated(final BillingChartRequest request); List<String> getAllBillingCenters();  }### Answer:
@Test public void shouldReturnPaginatedBillingChartInfoList() { when(mockBillingManager.getBillingChartInfoPaginated(billingChartRequest)).thenReturn(billingChartInfos); assertThat(billingApiService.getBillingChartInfoPaginated(billingChartRequest)).isEqualTo(billingChartInfos); }