static Map<String, Integer> readJson(String json) throws Exception {
    Map<String, Integer> result = new LinkedHashMap<>();
    JsonParser parser = new JsonFactory().createParser(json);
    assertThat(parser.nextToken()).isEqualTo(JsonToken.START_OBJECT);
    String nextField;
    while ((nextField = parser.nextFieldName()) != null) {
      result.put(nextField, parser.nextIntValue(0));
    }
    return result;
  }
Only add tests that do not consider the value of a counter or gauge, as these will flake and so
should only exist in {@link ITZipkinMetricsDirty}.
zipkin-server/src/test/java/zipkin2/server/internal/prometheus/ITZipkinMetrics.java