Set operations in Ruby

gistfile1.rb

# filename spec/fake_set_spec.rb
require 'spec_helper'
require 'fake_set'

describe FakeSet, '#union' do
  set1 = FakeSet.new(1, 2, 3)
  set2 = FakeSet.new(3, 4, 5)

  expect(set1.union(set2)).to eq FakeSet.new(1, 2, 3, 4, 5)
end

describe FakeSet, '#intersect' do
  set1 = FakeSet.new(1, 2, 3)
  set2 = FakeSet.new(3, 4, 5)

  expect(set1.intersect(set2)).to eq FakeSet.new(3)
end

describe FakeSet, '#difference' do
  set1 = FakeSet.new(1, 2, 3)
  set2 = FakeSet.new(3, 4, 5)

  expect(set1.difference(set2)).to eq FakeSet.new(1 ,2)
end