@Test public void errorSpan_JSON_V2() {

  assertThat(new String(encoder.encode(errorSpan), UTF_8))
      .isEqualTo(
          "{\"traceId\":\"dc955a1d4768875d\",\"id\":\"dc955a1d4768875d\",\"kind\":\"CLIENT\",\"localEndpoint\":{\"serviceName\":\"isao01\"},\"tags\":{\"error\":\"\"}}");
}