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: tag_test.rb
    path of file: ./repos/tracks/test/models
    
    the code of the file until where you have to start completion: require 'test_helper'

class TagTest 
    
  def test_tag_name_always_lowercase
    tag = Tag.where(:name => "UPPER").first_or_create
    assert !tag.new_record?

    upper = Tag.where(:name => "upper").first
    assert_not_nil upper
    assert upper.name == "upper"
  end