A DateRange value object, for those times you need to work with a range (or span) of dates (or really... datetimes)!

date_range.rb

# frozen_string_literal: true

require 'active_support'
require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/time'

class DateRange
  attr_reader :start, :stop

  def initialize(start: nil, stop: nil)
    @start = extract_date(start)
    @stop = extract_date(stop)
  end

  alias begin start
  alias :end stop

  def empty?
    start.blank? && stop.blank?
  end

  def present?
    !blank?
  end

  def start?
    start.present?
  end
  alias begin? start?

  def stop?
    stop.present?
  end
  alias :end? stop?

  private

  def extract_date(date)
    return nil if date.blank?

    Time.zone.parse(String(date)).to_date
  end
end

date_range_spec.rb

# frozen_string_literal: true

require 'date_range'

RSpec.describe DateRange do
  describe 'with no start nor stop' do
    subject(:range) { described_class.new }

    it 'is empty, blank' do
      expect(range).to be_empty
      expect(range).to be_blank
    end

    it 'is not present' do
      expect(range).not_to be_present
    end
  end

  describe 'converting strings to dates' do
    subject(:range) { described_class.new(start: '2017-04-20', stop: '2018-04-28') }

    it 'turns a valid date string into a date' do
      expect(range.start).to eq(Date.parse('2017-04-20'))
      expect(range.begin).to eq(Date.parse('2017-04-20'))

      expect(range.stop).to eq(Date.parse('2018-04-28'))
      expect(range.end).to eq(Date.parse('2018-04-28'))
    end

    it 'allows nil or empty dates' do
      nil_dates = described_class.new(start: nil, stop: nil)

      expect(nil_dates.start).to be_nil
      expect(nil_dates.stop).to be_nil

      empty_dates = described_class.new(start: '', stop: '')
      expect(empty_dates.start).to be_nil
      expect(empty_dates.stop).to be_nil
    end

    it 'blows up on a bad date' do
      expect { described_class.new(start: '2018-01') }.to raise_error(ArgumentError)

      expect { described_class.new(stop: '2018-01') }.to raise_error(ArgumentError)
    end
  end

  describe 'with date objects' do
    subject(:range) { described_class.new(start: Date.parse('2017-04-20'), stop: Date.parse('2018-04-28')) }

    it 'turns a valid date string into a date' do
      expect(range.start).to eq(Date.parse('2017-04-20'))
      expect(range.begin).to eq(Date.parse('2017-04-20'))

      expect(range.stop).to eq(Date.parse('2018-04-28'))
      expect(range.end).to eq(Date.parse('2018-04-28'))
    end
  end
end