@Test
  public void testSelectParams() {
    List<String> stats = new ArrayList<String>();
    stats.add("average");
    stats.add("min");
    stats.add("max");
    Set<BasicRollupsOutputSerializer.MetricStat> filters =
        PlotRequestParser.getStatsToFilter(stats);

    Assert.assertTrue(filters.contains(BasicRollupsOutputSerializer.MetricStat.AVERAGE));
    Assert.assertTrue(filters.contains(BasicRollupsOutputSerializer.MetricStat.MIN));
    Assert.assertTrue(filters.contains(BasicRollupsOutputSerializer.MetricStat.MAX));

    // Alternate comma delimited notation
    stats = new ArrayList<String>();
    stats.add("average,min,max");
    filters = PlotRequestParser.getStatsToFilter(stats);
    Assert.assertTrue(filters.contains(BasicRollupsOutputSerializer.MetricStat.AVERAGE));
    Assert.assertTrue(filters.contains(BasicRollupsOutputSerializer.MetricStat.MIN));
    Assert.assertTrue(filters.contains(BasicRollupsOutputSerializer.MetricStat.MAX));
  }
  @Override
  public void handle(ChannelHandlerContext ctx, HttpRequest request) {

    Tracker.getInstance().track(request);

    final String tenantId = request.getHeader("tenantId");

    if (!(request instanceof HTTPRequestWithDecodedQueryParams)) {
      sendResponse(
          ctx, request, "Missing query params: from, to, points", HttpResponseStatus.BAD_REQUEST);
      return;
    }

    final String body = request.getContent().toString(Constants.DEFAULT_CHARSET);

    if (body == null || body.isEmpty()) {
      sendResponse(
          ctx,
          request,
          "Invalid body. Expected JSON array of metrics.",
          HttpResponseStatus.BAD_REQUEST);
      return;
    }

    List<String> locators = new ArrayList<String>();
    try {
      locators.addAll(getLocatorsFromJSONBody(tenantId, body));
    } catch (Exception ex) {
      log.debug(ex.getMessage(), ex);
      sendResponse(ctx, request, ex.getMessage(), HttpResponseStatus.BAD_REQUEST);
      return;
    }

    if (locators.size() > maxMetricsPerRequest) {
      sendResponse(
          ctx,
          request,
          "Too many metrics fetch in a single call. Max limit is " + maxMetricsPerRequest + ".",
          HttpResponseStatus.BAD_REQUEST);
      return;
    }

    HTTPRequestWithDecodedQueryParams requestWithParams =
        (HTTPRequestWithDecodedQueryParams) request;
    final Timer.Context httpBatchMetricsFetchTimerContext = httpBatchMetricsFetchTimer.time();
    try {
      RollupsQueryParams params = PlotRequestParser.parseParams(requestWithParams.getQueryParams());
      Map<Locator, MetricData> results =
          getRollupByGranularity(
              tenantId,
              locators,
              params.getRange().getStart(),
              params.getRange().getStop(),
              params.getGranularity(tenantId));
      JSONObject metrics = serializer.transformRollupData(results, params.getStats());
      final JsonElement element = parser.parse(metrics.toString());
      final String jsonStringRep = gson.toJson(element);
      sendResponse(ctx, request, jsonStringRep, HttpResponseStatus.OK);
    } catch (InvalidRequestException e) {
      log.debug(e.getMessage());
      sendResponse(ctx, request, e.getMessage(), HttpResponseStatus.BAD_REQUEST);
    } catch (SerializationException e) {
      log.debug(e.getMessage(), e);
      sendResponse(ctx, request, e.getMessage(), HttpResponseStatus.INTERNAL_SERVER_ERROR);
    } catch (Exception e) {
      log.error(e.getMessage(), e);
      sendResponse(ctx, request, e.getMessage(), HttpResponseStatus.INTERNAL_SERVER_ERROR);
    } finally {
      httpBatchMetricsFetchTimerContext.stop();
    }
  }