gistfile1.rb

def hashfy(array)
   array.size > 1 ?  {array.shift => hashfy(array)} : array.shift
end

require "minitest/autorun"

describe "#hashfy" do
  it "converts an array to a nested hash" do
    hashfy([:animal, :dog]).must_equal({animal: :dog})
    hashfy([:animal, :mammal, :dog]).must_equal({animal: {mammal: :dog}})
  end
end