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_set.rb
    path of file: ./repos/truffleruby/test/mri/tests
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
require 'test/unit'
require 'set'

class TC_Set < Test::Unit::TestCase
  class Set2 < Set
  end

  def test_aref
    assert_nothing_raised {
      Set[]
      Set[nil]
      Set[1,2,3]
    }

    assert_equal(0, Set[].size)
    assert_equal(1, Set[nil].size)
    assert_equal(1, Set[[]].size)
    assert_equal(1, Set[[nil]].size)

    set = Set[2,4,6,4]
    assert_equal(Set.new([2,4,6]), set)
  end

  def test_s_new
    assert_nothing_raised {
      Set.new()
      Set.new(nil)
 
    
  def test_subset?
    set = Set[1,2,3]

    assert_raise(ArgumentError) {
      set.subset?()
    }

    assert_raise(ArgumentError) {
      set.subset?(2)
    }

    assert_raise(ArgumentError) {
      set.subset?([2])
    }

    [Set, Set2].each { |klass|
      assert_equal(true, set.subset?(klass[1,2,3,4]), klass.name)
      assert_equal(true, set.subset?(klass[1,2,3]), klass.name)
      assert_equal(false, set.subset?(klass[1,2]), klass.name)
      assert_equal(false, set.subset?(klass[]), klass.name)

      assert_equal(true, set <= klass[1,2,3], klass.name)
      assert_equal(true, set <= klass[1,2,3,4], klass.name)

      assert_equal(true, Set[].subset?(klass[1]), klass.name)
      assert_equal(true, Set[].subset?(klass[]), klass.name)
    }
  end