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_utf16.rb
    path of file: ./repos/artichoke/artichoke-backend/vendor/ruby/test/ruby/enc
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
require 'test/unit'

class TestUTF16 < Test::Unit::TestCase
  def encdump(obj)
    case obj
    when String
      d = obj.dump
      if /\.force_encoding\("[A-Za-z0-9.:_+-]*"\)\z/ =~ d
      
    
  def test_utf16le_valid_encoding
    all_assertions do |a|
      [
        "\x00\x00",
        "\xff\xd7",
        "\x00\xd8\x00\xdc",
        "\xff\xdb\xff\xdf",
        "\x00\xe0",
        "\xff\xff",
      ].each {|s|
        s.force_encoding("utf-16le")
        a.for(s) {
          assert_predicate(s, :valid_encoding?, "#{encdump s}.valid_encoding?")
        }
      }
      [
        "\x00",
        "\xd7",
        "\x00\xd8",
        "\x00\xd8\x00\xd8",
        "\x00\xdc",
        "\x00\xdc\x00\xd8",
        "\x00\xdc\x00\xdc",
        "\xe0",
        "\xff",
      ].each {|s|
        s.force_encoding("utf-16le")
        a.for(s) {
          assert_not_predicate(s, :valid_encoding?, "#{encdump s}.valid_encoding?")
        }
      }
    end
  end