TestData's @DaTa is a Hash that defaults to empty Hashes?

my_given_driver.rb

class MyGivenDriver < Kookaburra::GivenDriver
  def a_bar(name)
    bar_data = test_data.default(:bar)
    record = api.create_bar(bar_data)
    test_data.set_bars(name, record)
  end

  def a_foo(name, bar_name)
    foo_data = test_data.default(:foo)

    # I didn't expect `bar` to ever be nil, but it was. See comment in `#fetch_bar`
    bar = fetch_bar(bar_name)

    foo_data[:bar_id] = bar.id
    record = api.create_foo(foo_data)
    test_data.set_foos(name, record)
  end

  private

  def fetch_bar(name)
    # The fact that the first method call here didn't return nil even when
    # the specified name was definitely *not* in the collection yet was
    # very surprising to me
    test_data.bars(name) || begin
      a_bar(name)
      test_data.fetch_bars(name)
    end
  end
end

...apparently you can also write Haskell in any language.