Logic Gates Code Challenge

logic_gates.rb

module And
  class Double
    attr_accessor :input_a,
                  :input_b

    def initialize
      @input_a = 0
      @input_b = 0
    end

    def output
      (input_a + input_b) == 2 ? 1 : 0
    end
  end

  class Triple
    attr_accessor :input_a,
                  :input_b,
                  :input_c

    def initialize
      @input_a = 0
      @input_b = 0
      @input_c = 0
    end

    def output
      (input_a + input_b + input_c) == 3 ? 1 : 0
    end
  end

  class Multi
    ALPHABET = ('a'..'z').to_a

    ALPHABET.each do |chr|
      define_method("input_#{chr}") do
        instance_variable_get("@input_#{chr}")
      end
      
      define_method("input_#{chr}=") do |value|
        instance_variable_set("@input_#{chr}", value)
      end
    end

    attr_reader :inputs

    def initialize(inputs)
      @inputs = inputs
      create_inputs
    end

    def create_inputs
      ALPHABET.each do |chr|
        instance_variable_set("@input_#{chr}", 0)
      end
    end

    def output
      inputs == sum ? 1 : 0
    end

    private

    def sum
      ALPHABET.reduce(0) { |sum, char| sum += send("input_#{char}") }
    end
  end
end

logic_gates_test.rb

require 'minitest/autorun'
require 'minitest/pride'
require './logic_gates'

class LogicGatesTest < Minitest::Test
  def test_double
    gate = And::Double.new
    gate.input_a = 1
    gate.input_b = 1

    assert_equal 1, gate.output

    gate.input_b = 0

    assert_equal 0, gate.output
  end

  def test_triple
    gate = And::Triple.new

    gate.input_a = 1
    gate.input_b = 1
    assert_equal 0, gate.output # => 0

    gate.input_c = 1
    assert_equal 1, gate.output # => 1

    gate.input_a = 0
    assert_equal 0, gate.output # => 0
  end

  def test_multi
    gate = And::Multi.new(4)
    
    gate.input_a = 1
    gate.input_b = 1
    gate.input_c = 1
    assert_equal 0, gate.output # => 0
    gate.input_d = 1
    assert_equal 1, gate.output # => 1
    gate.input_b = 0
    assert_equal 0, gate.output # => 0
  end
end