Set + minitest/spec

set_spec.rb

require 'minitest/autorun'

class SetTest < MiniTest::Spec
  before do
    @set = Set.new
  end

  specify '#size' do
    @set.size.must_equal 0
    @set.add 42
    @set.size.must_equal 1
  end

  specify '#include?' do
    @set.include?(42).must_equal false
    @set.add 42
    @set.include?(42).must_equal true
  end

  specify '#add' do
    @set.add 13
    @set.add 13
    @set.size.must_equal 1
  end

  specify '#to_a' do
    @set.add 1
    @set.add 4
    @set.add 2

    ary = @set.to_a

    ary.size.must_equal 3
    ary.must_include 1
    ary.must_include 2
    ary.must_include 4
  end
end

class Set
  include Enumerable

  def initialize
    @hash = {}
  end

  def size
    @hash.size
  end

  def add(obj)
    @hash[obj] = true
  end

  def include?(obj)
    @hash.include? obj
  end

  def each(&block)
    @hash.keys.each(&block)
  end
end

class SortedSetTest < SetTest
  before do
    @set = SortedSet.new
  end

  specify '#to_a' do
    @set.add 1
    @set.add 4
    @set.add 2
    @set.to_a.must_equal [1, 2, 4]
  end
end

class SortedSet < Set
  def each(&block)
    @hash.keys.sort.each(&block)
  end
end