@Test void dailyIndexFormat_overridingDateSeparator() {
    TestPropertyValues.of(
      "zipkin.storage.type:elasticsearch",
      "zipkin.storage.elasticsearch.hosts:http://host1:9200",
      "zipkin.storage.elasticsearch.date-separator:.")
      .applyTo(context);
    Access.registerElasticsearch(context);
    context.refresh();

    assertThat(es().indexNameFormatter().formatTypeAndTimestamp("span", 0))
      .isEqualTo("zipkin*span-1970.01.01");
  }
Ensures we can wire up network interceptors, such as for logging or authentication
zipkin-server/src/test/java/zipkin2/server/internal/elasticsearch/ZipkinElasticsearchStorageConfigurationTest.java