Encode & decode strings Ruby

Encode & decode strings Ruby

class RunLengthEncoding

  def self.encode(input)
    new_array = split_by_chars input
    ordered  = new_array.map do |el|
      el.length > 1 ? "#{el.length}#{el.chr}" : el
    end.join
  end

  def self.decode(input)
    tempo = split_by_numbers input
    tempo.map.with_index(0) do |e, i|
      if is_integer?(e)
        tempo[i+1] * e.to_i
      elsif num?(e) == false && num?(tempo[i-1]) == false
        e
      end
    end.join
  end

  def self.split_by_chars(my_str)
    my_str.scan(/((\w|\s)\2*)/).map(&:first)
  end

  def self.split_by_numbers(my_str)
    my_str.each_char.slice_when{ |a,b| is_integer?(a) != is_integer?(b) || !is_integer?(a) && !is_integer?(b)}.map(&:join)
  end

  def self.num?(e)
    numero = Integer(e) rescue false
    numero.is_a?(Integer)
  end

  def self.is_integer?(str)
    str.to_i.to_s == str
  end

end

# TEST

def test_encode_with_repeated_characters
    output = '12WB12W3B24WB'
    input = 'WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB'
    assert_equal output, RunLengthEncoding.encode(input)
end

def test_decode_with_repeated_characters
    input = '12WB12W3B24WB'
    output = 'WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWB'
    assert_equal output, RunLengthEncoding.decode(input)
end