@Test void nullToZeroOrFalse() {
    Span nulls = base.toBuilder()
      .timestamp(null)
      .duration(null)
      .build();

    Span zeros = base.toBuilder()
      .timestamp(0L)
      .duration(0L)
      .build();

    assertThat(nulls)
      .isEqualToComparingFieldByField(zeros);
  }
Catches common error when zero is passed instead of null for a timestamp
zipkin/src/test/java/zipkin2/SpanTest.java