@VisibleForTesting
  static boolean isUriValid(String uri) {
    Matcher matcher = URI_PATTERN.matcher(uri);
    return matcher.matches();
  }
@Test
  public void testInvalidUri() {
    assertThat(
            HttpCacheServerHandler.isUriValid(
                "http://localhost:8080/ac_e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"))
        .isFalse();
    assertThat(
            HttpCacheServerHandler.isUriValid(
                "http://localhost:8080/cas_e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"))
        .isFalse();
    assertThat(HttpCacheServerHandler.isUriValid("http://localhost:8080/ac/111111111111111111111"))
        .isFalse();
    assertThat(HttpCacheServerHandler.isUriValid("http://localhost:8080/cas/111111111111111111111"))
        .isFalse();
    assertThat(HttpCacheServerHandler.isUriValid("http://localhost:8080/cas/823rhf&*%OL%_^"))
        .isFalse();
    assertThat(HttpCacheServerHandler.isUriValid("http://localhost:8080/ac/823rhf&*%OL%_^"))
        .isFalse();
  }