@Test void setsCacheControlOnAutocompleteEndpointWhenMoreThan3Values() throws Exception {
    assertThat(get("/api/v2/autocompleteValues?key=environment").header("Cache-Control"))
      .isNull();
    assertThat(get("/api/v2/autocompleteValues?key=clnt/finagle.version").header("Cache-Control"))
      .isNull();

    for (int i = 0; i < 4; i++) {
      post("/api/v2/spans", SpanBytesEncoder.JSON_V2.encodeList(List.of(
        Span.newBuilder().traceId("a").id(i + 1).timestamp(TODAY).name("whopper")
          .putTag("clnt/finagle.version", "6.45." + i).build()
      )));
    }

    assertThat(get("/api/v2/autocompleteValues?key=environment").header("Cache-Control"))
      .isNull();
    assertThat(get("/api/v2/autocompleteValues?key=clnt/finagle.version").header("Cache-Control"))
      .isEqualTo("max-age=300, must-revalidate");
  }
Integration test suite for autocomplete tags.
<p>
Verifies that the whitelist of key can be configured via "zipkin.storage.autocomplete-keys".
zipkin-server/src/test/java/zipkin2/server/internal/ITZipkinServerAutocomplete.java