java8收集器嵌套用法，在接口測試中的應用

複雜業務數據結構，原始測試斷言不那麼直觀，例如如下數據結構，是一個支付業務中，營銷查詢返回結果，按銀行卡掛載優惠信息。

{
  "banks": [
    {
      "bankcardId": 131794663,
      "banktype": 36,
      "promotionDetails": [
        {
          "camId": 7918,
          "camType": 1,
          "merchantId": "11000000044187",
          "reduce": "10.00"
        },
        {
          "camId": 7916,
          "camType": 1,
          "merchantId": "1020700305",
          "reduce": "1.00"
        }
      ],
      "totalReduce": "11.00"
    },
    {
      "bankcardId": 131799485,
      "banktype": 62,
      "promotionDetails": [
        {
          "camId": 7917,
          "camType": 1,
          "merchantId": "11000000044187",
          "reduce": "26.62"
        },
        {
          "camId": 7920,
          "camType": 1,
          "merchantId": "1020700305",
          "reduce": "1.90"
        }
      ],
      "totalReduce": "28.52"
    }
  ],
  "promotionId": "1578632750975",
  "resCode": "SUCCESS",
  "resMsg": "SUCCESS"
}

  需要對接口返回數據做驗證，驗證某行掛載優惠信息是否正確：

  1.結果預處理，化繁爲簡，使用嵌套的蒐集器，並轉換爲指定的數據類型，這裏按銀行類型分組，嵌套蒐集各類型銀行優惠活動id及優惠金額：

    private Map<Integer, Map<Integer, String>> getBankCamReduceMap(DiscountInfoResponseDTO discountInfoResponseDTO) {
        return discountInfoResponseDTO.getBanks().stream().collect(groupingBy(BankCard::getBanktype,
                collectingAndThen(
                        mapping(bankCard -> {
                            return bankCard.getPromotionDetails().stream().collect(toMap(PromotionDetailDTO::getCamId, PromotionDetailDTO::getReduce));
                        }, toSet()),
                        set -> set.stream().findFirst().get())));
    }

2.測試：check reduce info.

    @Test(description = "")
    public void testBatchQuery_group() throws Exception {
        PromoQueryRequest promoQueryRequest = PromoQueryRequestBuilder
                .aPromoQueryRequest()
                .withChannel("jszf")
                .withBusinessId(String.valueOf(genLongSerialNo()))
                .withBusinessParams(JSON.toJSONString(businessParams))
                .withUser(UserBuilder.anUser().withUserId(34534534643L).build())
                .build();

        DiscountInfoResponseDTO discountInfoResponseDTO = promoBatchQueryService.batchQuery(promoQueryRequest);

        printPrettyJson(discountInfoResponseDTO);
        assertThat(discountInfoResponseDTO.getResCode()).isEqualTo("SUCCESS");
        assertThat(Long.parseLong(discountInfoResponseDTO.getPromotionId())).isGreaterThan(0);


        //check reduce info.
        Map<Integer, Map<Integer, String>> bankCamReduceMap = getBankCamReduceMap(discountInfoResponseDTO);
        printPrettyJson(bankCamReduceMap);
        assertThat(bankCamReduceMap.get(36))
                .containsEntry(7916, "1.00")
                .containsEntry(7918, "10.00");
        assertThat(bankCamReduceMap.get(62))
                .hasSize(2)
                .containsEntry(7920, "1.90");
        assertThat(Double.parseDouble(bankCamReduceMap.get(62).get(7917))).isBetween(21.00, 30.00); //隨機減
        boolean totalReduceIsRight = isTotalReduceIsRight(discountInfoResponseDTO);
        assertThat(totalReduceIsRight).isTrue();

    }

斷言就清爽了許多。