Simplistic approach to calculate image aspect ratio

aspect_ratio.rb

# frozen_string_literal: true

class AspectRatio
  attr_reader :width, :height

  def initialize(width, height)
    @width = width
    @height = height
  end

  def aspect_ratio
    @aspect_ratio ||= Rational(width, height).to_s.tr("/", ":")
  end

  def orientation
    @orientation ||= width >= height ? :landscape : :portrait
  end

  def portrait?
    orientation == :portrait
  end

  def landscape?
    !portrait?
  end
end

def AspectRatio(width, height) # rubocop:disable Naming/MethodName
  AspectRatio.new(width, height)
end

if $PROGRAM_NAME == __FILE__
  require "bundler/inline"

  gemfile do
    source "https://rubygems.org"
    gem "minitest-utils"
  end

  require "minitest"
  require "minitest/autorun"
  require "minitest/utils"

  class AspectRatioTest < Minitest::Test
    [
      [1920, 1080, "16:9", :landscape],
      [3840, 2160, "16:9", :landscape],
      [2160, 3840, "9:16", :portrait],
      [500, 500, "1:1", :landscape],
      [600, 400, "3:2", :landscape],
      [400, 600, "2:3", :portrait]
    ].each do |(width, height, aspect_ratio, orientation)|
      test "detects #{width}x#{height} as #{aspect_ratio}" do
        info = AspectRatio(width, height)
        assert_equal aspect_ratio, info.aspect_ratio
        assert_equal orientation, info.orientation
      end
    end

    test "detects portrait aspect ratio" do
      assert AspectRatio(1080, 1920).portrait?
      refute AspectRatio(1080, 1920).landscape?
    end

    test "detects landscape aspect ratio" do
      assert AspectRatio(1920, 1080).landscape?
      refute AspectRatio(1920, 1080).portrait?
    end
  end
end