Ruby custom implementation of Array#flatten using Regular Expressions

flattener.rb

x = [[1], [2, 3, [4, 5, 6, [7, 8, 9, 10], 11], 12, 13], 14, 15, 16]

class Array
  def flattener
    matches = self.to_s.scan(/\d+/)
    matches.collect(&:to_i)
  end
end

puts "Specs"
puts "====="

cases = [
  [],
  [1, [2]],
  [1, [2, [3]]],
  [1, [[2, 3], 4], 5],
  [1, [2, [3, 4]], 5, [6,[7]]],
  [1, [2, [3, 4], [5, 6, [7, 8, [9, 10, 11], [12]]]], 13, [14, 15], [16]]
]

cases.each_with_index do |the_case, i|
  p "#{i}. #{the_case}"
  ruby_one = the_case.flatten
  custom_one = the_case.flattener
  p "ruby_one: #{ruby_one}"
  p "custom_one: #{custom_one}"
  puts (ruby_one == custom_one) ? "pass" : "fail"
end