@Test public void nextSpan_fromFlags_resultantSpanIsLocalRoot() {

  Span span = tracer.nextSpan(TraceContextOrSamplingFlags.create(SamplingFlags.SAMPLED));
  assertThat(span.context().spanId()).isEqualTo(span.context().localRootId()); // Sanity check
  assertThat(span.context().isLocalRoot()).isTrue();
}