@Udf
  public String extractQuery(
      @UdfParameter(description = "a valid URL to extract a query from") final String input) {
    return UrlParser.extract(input, URI::getQuery);
  }
@Test
  public void shouldReturnNullIfNoQuery() {
    assertThat(extractUdf.extractQuery("https://current/ksql/docs/syntax-reference.html#scalar-functions"), nullValue());
  }