@Test
  public void testCopyHeadersClusterAdminRequest() {
    Map<String, String> transportHeaders = randomHeaders(randomIntBetween(0, 10));
    Map<String, String> restHeaders = randomHeaders(randomIntBetween(0, 10));
    Map<String, String> copiedHeaders = randomHeadersFrom(restHeaders);
    Set<String> usefulRestHeaders = new HashSet<>(copiedHeaders.keySet());
    usefulRestHeaders.addAll(randomMap(randomIntBetween(0, 10), "useful-").keySet());
    Map<String, String> restContext = randomContext(randomIntBetween(0, 10));
    Map<String, String> transportContext =
        Maps.difference(randomContext(randomIntBetween(0, 10)), restContext).entriesOnlyOnLeft();

    HashMap<String, String> expectedHeaders = new HashMap<>();
    expectedHeaders.putAll(transportHeaders);
    expectedHeaders.putAll(copiedHeaders);

    Map<String, String> expectedContext = new HashMap<>();
    expectedContext.putAll(transportContext);
    expectedContext.putAll(restContext);

    Client client =
        client(
            new NoOpClient(), new FakeRestRequest(restHeaders, expectedContext), usefulRestHeaders);

    ClusterHealthRequest clusterHealthRequest = Requests.clusterHealthRequest();
    putHeaders(clusterHealthRequest, transportHeaders);
    putContext(clusterHealthRequest, transportContext);
    assertHeaders(clusterHealthRequest, transportHeaders);
    client.admin().cluster().health(clusterHealthRequest);
    assertHeaders(clusterHealthRequest, expectedHeaders);
    assertContext(clusterHealthRequest, expectedContext);

    ClusterStateRequest clusterStateRequest = Requests.clusterStateRequest();
    putHeaders(clusterStateRequest, transportHeaders);
    putContext(clusterStateRequest, transportContext);
    assertHeaders(clusterStateRequest, transportHeaders);
    client.admin().cluster().state(clusterStateRequest);
    assertHeaders(clusterStateRequest, expectedHeaders);
    assertContext(clusterStateRequest, expectedContext);

    ClusterStatsRequest clusterStatsRequest = Requests.clusterStatsRequest();
    putHeaders(clusterStatsRequest, transportHeaders);
    putContext(clusterStatsRequest, transportContext);
    assertHeaders(clusterStatsRequest, transportHeaders);
    client.admin().cluster().clusterStats(clusterStatsRequest);
    assertHeaders(clusterStatsRequest, expectedHeaders);
    assertContext(clusterStatsRequest, expectedContext);
  }
  @Test
  public void testCopyHeadersRequest() {
    Map<String, String> transportHeaders = randomHeaders(randomIntBetween(0, 10));
    Map<String, String> restHeaders = randomHeaders(randomIntBetween(0, 10));
    Map<String, String> copiedHeaders = randomHeadersFrom(restHeaders);
    Set<String> usefulRestHeaders = new HashSet<>(copiedHeaders.keySet());
    usefulRestHeaders.addAll(randomMap(randomIntBetween(0, 10), "useful-").keySet());
    Map<String, String> restContext = randomContext(randomIntBetween(0, 10));
    Map<String, String> transportContext =
        Maps.difference(randomContext(randomIntBetween(0, 10)), restContext).entriesOnlyOnLeft();

    Map<String, String> expectedHeaders = new HashMap<>();
    expectedHeaders.putAll(transportHeaders);
    expectedHeaders.putAll(copiedHeaders);

    Map<String, String> expectedContext = new HashMap<>();
    expectedContext.putAll(transportContext);
    expectedContext.putAll(restContext);

    Client client =
        client(new NoOpClient(), new FakeRestRequest(restHeaders, restContext), usefulRestHeaders);

    SearchRequest searchRequest = Requests.searchRequest();
    putHeaders(searchRequest, transportHeaders);
    putContext(searchRequest, transportContext);
    assertHeaders(searchRequest, transportHeaders);
    client.search(searchRequest);
    assertHeaders(searchRequest, expectedHeaders);
    assertContext(searchRequest, expectedContext);

    GetRequest getRequest = Requests.getRequest("index");
    putHeaders(getRequest, transportHeaders);
    putContext(getRequest, transportContext);
    assertHeaders(getRequest, transportHeaders);
    client.get(getRequest);
    assertHeaders(getRequest, expectedHeaders);
    assertContext(getRequest, expectedContext);

    IndexRequest indexRequest = Requests.indexRequest();
    putHeaders(indexRequest, transportHeaders);
    putContext(indexRequest, transportContext);
    assertHeaders(indexRequest, transportHeaders);
    client.index(indexRequest);
    assertHeaders(indexRequest, expectedHeaders);
    assertContext(indexRequest, expectedContext);
  }
  @Test
  public void testCopyHeadersIndicesAdminRequest() {
    Map<String, String> transportHeaders = randomHeaders(randomIntBetween(0, 10));
    Map<String, String> restHeaders = randomHeaders(randomIntBetween(0, 10));
    Map<String, String> copiedHeaders = randomHeadersFrom(restHeaders);
    Set<String> usefulRestHeaders = new HashSet<>(copiedHeaders.keySet());
    usefulRestHeaders.addAll(randomMap(randomIntBetween(0, 10), "useful-").keySet());
    Map<String, String> restContext = randomContext(randomIntBetween(0, 10));
    Map<String, String> transportContext =
        Maps.difference(randomContext(randomIntBetween(0, 10)), restContext).entriesOnlyOnLeft();

    HashMap<String, String> expectedHeaders = new HashMap<>();
    expectedHeaders.putAll(transportHeaders);
    expectedHeaders.putAll(copiedHeaders);

    Map<String, String> expectedContext = new HashMap<>();
    expectedContext.putAll(transportContext);
    expectedContext.putAll(restContext);

    Client client =
        client(new NoOpClient(), new FakeRestRequest(restHeaders, restContext), usefulRestHeaders);

    CreateIndexRequest createIndexRequest = Requests.createIndexRequest("test");
    putHeaders(createIndexRequest, transportHeaders);
    putContext(createIndexRequest, transportContext);
    assertHeaders(createIndexRequest, transportHeaders);
    client.admin().indices().create(createIndexRequest);
    assertHeaders(createIndexRequest, expectedHeaders);
    assertContext(createIndexRequest, expectedContext);

    CloseIndexRequest closeIndexRequest = Requests.closeIndexRequest("test");
    putHeaders(closeIndexRequest, transportHeaders);
    putContext(closeIndexRequest, transportContext);
    assertHeaders(closeIndexRequest, transportHeaders);
    client.admin().indices().close(closeIndexRequest);
    assertHeaders(closeIndexRequest, expectedHeaders);
    assertContext(closeIndexRequest, expectedContext);

    FlushRequest flushRequest = Requests.flushRequest();
    putHeaders(flushRequest, transportHeaders);
    putContext(flushRequest, transportContext);
    assertHeaders(flushRequest, transportHeaders);
    client.admin().indices().flush(flushRequest);
    assertHeaders(flushRequest, expectedHeaders);
    assertContext(flushRequest, expectedContext);
  }