You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: test_encoding_handler.rb
    path of file: ./repos/stackneveroverflow/vendor/bundle/ruby/2.3.0/gems/nokogiri-1.8.0/test
    
    the code of the file until where you have to start completion: # -*- coding: utf-8 -*-

require "helper"

class TestEncodingHandler < Nokogiri::TestCase
  def teardown
    Nokogiri::Enc
    
  def test_delete
    assert_nil Nokogiri::EncodingHandler['UTF-9']
    Nokogiri::EncodingHandler.alias('UTF-8', 'UTF-9')
    assert_not_nil Nokogiri::EncodingHandler['UTF-9']

    Nokogiri::EncodingHandler.delete 'UTF-9'
    assert_nil Nokogiri::EncodingHandler['UTF-9']
  end