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_gem.rb
    path of file: ./repos/truffleruby/test/mri/tests/rubygems
    
    the code of the file until where you have to start completion: # coding: US-ASCII
require_relative "helper"
require "rubygems"
require "rubygems/command"
require "rubygems/installer"
require "pathname"
require "tmpdir"
require "rbconfig"

class TestGem < Gem::TestCase
  PLUGINS_LOADED = [] # rubocop:d
    
  def test_self_env_requirement
    ENV["GEM_REQUIREMENT_FOO"] = ">= 1.2.3"
    ENV["GEM_REQUIREMENT_BAR"] = "1.2.3"
    ENV["GEM_REQUIREMENT_BAZ"] = "abcd"

    assert_equal Gem::Requirement.create(">= 1.2.3"), Gem.env_requirement("foo")
    assert_equal Gem::Requirement.create("1.2.3"), Gem.env_requirement("bAr")
    assert_raise(Gem::Requirement::BadRequirementError) { Gem.env_requirement("baz") }
    assert_equal Gem::Requirement.default, Gem.env_requirement("qux")
  end