@Test void getTrace_malformedDoesntUpdateCollectorMetrics() throws Exception {
    double messagesCount =
      registry.counter("zipkin_collector.messages", "transport", "http").count();
    double messagesDroppedCount =
      registry.counter("zipkin_collector.messages_dropped", "transport", "http").count();

    Response response = get("/api/v2/trace/0e8b46e1-81b");
    assertThat(response.code()).isEqualTo(400);

    String json = getAsString("/metrics");

    assertThat(readDouble(json, "$.['counter.zipkin_collector.messages.http']"))
      .isEqualTo(messagesCount);
    assertThat(readDouble(json, "$.['counter.zipkin_collector.messages_dropped.http']"))
      .isEqualTo(messagesDroppedCount);
  }
This tests logic in {@code BodyIsExceptionMessage} is scoped to POST requests.
zipkin-server/src/test/java/zipkin2/server/internal/prometheus/ITZipkinMetricsDirty.java