public Map<String, Object> internalJson(Histogram histogram) {
        HistogramSchema histogramSchema = histogram.getHistogramSchema();

        return Map.ofEntries(entry(histogramSchema.getFastSlot(), histogram.getFastCount()),
                entry(histogramSchema.getNormalSlot(), histogram.getNormalCount()),
                entry(histogramSchema.getSlowSlot(), histogram.getSlowCount()),
                entry(histogramSchema.getVerySlowSlot(), histogram.getVerySlowCount()),
                entry(histogramSchema.getTotalErrorView(), histogram.getTotalErrorCount())
        );
    }
moved this testcase for testing the old version histogram with manually created json code
web/src/test/java/com/navercorp/pinpoint/web/view/HistogramSerializerTest.java