SpanId { public boolean isValid() { return spanId != 0; } SpanId(long spanId); static SpanId invalid(); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString(); boolean isValid(); long getSpanId(); String getApiString();  }
@Test public void testIsValid() { assertThat(first.isValid()).isTrue(); assertThat(invalid.isValid()).isFalse(); }