@VisibleForTesting
  Iterator<UdfProvider> getUdfProviders(ClassLoader classLoader) throws IOException {
    return ServiceLoader.load(UdfProvider.class, classLoader).iterator();
  }
@Test
  public void testClassLoaderHasNoUdfProviders() throws IOException {
    JavaUdfLoader udfLoader = new JavaUdfLoader();
    Iterator<UdfProvider> udfProviders =
        udfLoader.getUdfProviders(ReflectHelpers.findClassLoader());
    assertFalse(udfProviders.hasNext());
  }