BitmaskOptions (spec)

require 'spec_helper'

shared_examples_for 'bitmask_options' do
  # http://stackoverflow.com/questions/16525222/how-to-test-a-concern-in-rails#answer-20010923
  # http://stackoverflow.com/questions/25562639/rspec-testing-ar-model-concern-within-described-class-or-dummyclass
  let(:model) { described_class } # the class that includes the concern

  has_attributes :bitmask_options

  it 'has at least one option' do
    expect(model.all_options).to have_at_least(1).item
  end

  context 'batch (array) setters' do
    it 'can set each option (true)' do
      model.all_options.each.with_index do |option, index|
        subject.bitmask_options += [option]
        expect(subject.bitmask_options).to include(option)
      end
    end

    it 'can unset each option (to false)' do
      model.all_options.each.with_index do |option, index|
        subject.bitmask_options -= [option]
        expect(subject.bitmask_options).to_not include(option)
      end
    end
  end

  context 'boolean setters' do
    it 'can set each option (true)' do
      model.all_options.each.with_index do |option, index|
        subject.send("#{option}=", true)
        expect(subject.send("#{option}")).to be true
      end
    end

    it 'can unset each option (false)' do
      model.all_options.each.with_index do |option, index|
        subject.send("#{option}=", false)
        expect(subject.send("#{option}")).to be false
      end
    end
  
    it 'does not modify other options when setting one (true)' do
      subject.bitmask = 0
      model.all_options.shuffle.each do |option|
        bitmask_before = subject.bitmask
        subject.send("#{option}=", true)
        bitmask_after = subject.bitmask
        expect(bitmask_before ^ bitmask_after).to be (1 << model.all_options.index(option))
      end
    end

    it 'does not modify other options when unsetting one (false)' do
      subject.bitmask = (1 << model.all_options.count) - 1
      model.all_options.shuffle.each do |option|
        bitmask_before = subject.bitmask
        subject.send("#{option}=", false)
        bitmask_after = subject.bitmask
        expect(bitmask_before ^ bitmask_after).to be (1 << model.all_options.index(option))
      end
    end
  end

end