@Test void getSpanNames_skipsNullSpanName() throws IOException {
    Span span1 = Span.newBuilder().traceId("1").id("1").name("root")
      .localEndpoint(Endpoint.newBuilder().serviceName("app").build())
      .timestamp(TODAY * 1000)
      .build();

    Span span2 = Span.newBuilder().traceId("1").parentId("1").id("2")
      .localEndpoint(Endpoint.newBuilder().serviceName("app").build())
      .timestamp(TODAY * 1000)
      .build();

    storage.accept(List.of(span1, span2)).execute();

    assertThat(storage.getSpanNames("app").execute()).containsOnly(
      "root"
    );
  }
It should be safe to run dependency link jobs twice
zipkin/src/test/java/zipkin2/storage/InMemoryStorageTest.java