hwia_spec.rb

class HashWithIndifferentAccess < Hash
  def [](key)
    super(convert_key(key))
  end

  def []=(key, value)
    super(convert_key(key), value)
  end

  def self.[] (*args)
    mapped_args = args.each_with_index.map{ |arg, i| i.even? ? convert_key(arg) : arg }
    super(*mapped_args)
  end

  def convert_key(key)
    self.class.convert_key(key)
  end

  def self.convert_key(key)
    key.to_sym
  end

  def store(key, value)
    super(convert_key(key), value)
  end

  def fetch(key, *args)
    super(convert_key(key), *args)
  end
end

describe HashWithIndifferentAccess do
  let(:h) { HashWithIndifferentAccess.new }

  it 'can save string, read symbol' do
    h['foo'] = 'bar'
    expect(h[:foo]).to eq('bar')
  end

  it 'can save symbol, read string' do
    h[:foo] = 'bar'
    expect(h['foo']).to eq('bar')
  end

  it 'can be initialized with a list of k,v pairs' do
    h2 = HashWithIndifferentAccess['foo', 'bar', :bar, 'baz']

    expect(h2[:foo]).to eq('bar')
    expect(h2['bar']).to eq('baz')
  end

  it 'can store' do
    h.store('foo', 'bar')
    expect(h[:foo]).to eq('bar')
  end

  it 'can fetch' do
    h[:foo] = 'bar'
    expect(h.fetch('foo')).to eq('bar')
  end
end