String Calculator Kata in Ruby - using enumerable methods

string_calculator_spec.rb

# Solving the String Calculator Kata
# http://osherove.com/tdd-kata-1/

class StringCalculator
  def self.add(numbers)
    return 0 if numbers.empty?

    numbers.split(",").map(&:to_i).reduce(:+)

    #splitted_array = numbers.split(",")

    #splitted_array.map! do |element|
      #element.to_i
    #end

    #splitted_array.inject(0) do |sum, element|
      #sum += element
    #end
  end
end

RSpec.describe StringCalculator do
  it("returns 0 for empty string") do
    result = StringCalculator.add("")
    expect(result).to eq(0)
  end

  it("returns 1 for '1'") do
    result = StringCalculator.add("1")
    expect(result).to eq(1)
  end

  it("returns 3 for '1,2'") do
    result = StringCalculator.add("1,2")
    expect(result).to eq(3)
  end
end