Checking if a string includes only allowed characters - a comparision of using chars.all? vs. regular expressions

chars_all_vs_regexp.rb

require 'benchmark'

module CharsAllVsRegexp
  VALID_CHARS = %w(A C G T)
  REGEXP = Regexp.new("\\A(#{ VALID_CHARS.join('|') })*\\z")
  ARRAY_LENGTH = 10000
  STRING_LENGTH = 5000

  STRINGS_GENERATOOR = ->(chars) do
    ARRAY_LENGTH.times.with_object([]) do |n, strings|
      strings << STRING_LENGTH.times.with_object('') { |n, string| string << chars.sample }
    end
  end

  def self.validate_via_regexp(string)
    string =~ REGEXP
  end

  def self.validate_via_chars_all(string)
    string.chars.all? { |char| VALID_CHARS.include?(char) }
  end

  def self.run
    puts 'Generating strings...'
    random_strings = STRINGS_GENERATOOR.call(('A'..'Z').to_a)
    valid_strings = STRINGS_GENERATOOR.call(VALID_CHARS)

    puts 'Running benchmark...'
    puts "Validating #{ ARRAY_LENGTH } random strings, each #{ STRING_LENGTH } characters long:"

    Benchmark.bm(15) do |x|
      x.report('regexp:') { random_strings.each { |string| validate_via_regexp(string)} }
      x.report('chars.all?:') { random_strings.each { |string| validate_via_chars_all(string)} }
    end

    puts "Validating #{ ARRAY_LENGTH } valid strings, each #{ STRING_LENGTH } characters long:"

    Benchmark.bm(15) do |x|
      x.report('regexp:') { valid_strings.each { |string| validate_via_regexp(string)} }
      x.report('chars.all?:') { valid_strings.each { |string| validate_via_chars_all(string)} }
    end
  end
end

CharsAllVsRegexp.run