    @Rule public ZipkinRule server = new ZipkinRule();
    HttpStorage storage = new HttpStorage(server.httpUrl());

    @Override protected HttpStorage storage() {
      return storage;
    }

    @Override public void clear() {
      // no need.. the test rule does this
    }
  }

  public static class SpanStoreTest extends zipkin.storage.SpanStoreTest {
    @Rule public ZipkinRule server = new ZipkinRule();