class RSpec::Core::ExampleGroup

def self.set_it_up(description, args, registration_collection, &example_group_block)
  # Ruby 1.9 has a bug that can lead to infinite recursion and a
  # SystemStackError if you include a module in a superclass after
  # including it in a subclass: https://gist.github.com/845896
  # To prevent this, we must include any modules in
  # RSpec::Core::ExampleGroup before users create example groups and have
  # a chance to include the same module in a subclass of
  # RSpec::Core::ExampleGroup. So we need to configure example groups
  # here.
  ensure_example_groups_are_configured
  # Register the example with the group before creating the metadata hash.
  # This is necessary since creating the metadata hash triggers
  # `when_first_matching_example_defined` callbacks, in which users can
  # load RSpec support code which defines hooks. For that to work, the
  # examples and example groups must be registered at the time the
  # support code is called or be defined afterwards.
  # Begin defined beforehand but registered afterwards causes hooks to
  # not be applied where they should.
  registration_collection << self
  @user_metadata = Metadata.build_hash_from(args)
  @metadata = Metadata::ExampleGroupHash.create(
    superclass_metadata, @user_metadata,
    superclass.method(:next_runnable_index_for),
    description, *args, &example_group_block
  )
  config = RSpec.configuration
  config.apply_derived_metadata_to(@metadata)
  ExampleGroups.assign_const(self)
  @currently_executing_a_context_hook = false
  config.configure_group(self)
end