# File lib/deltacloud/drivers/mock/mock_driver.rb, line 202
  def update_instance_state(credentials, id, state)
    instance_file = "#{@storage_root}/instances/#{id}.yml"
    instance_yml  = YAML.load( File.read( instance_file ) )
    instance_yml[:id] = id
    instance_yml[:state] = state
    instance_yml[:actions] = instance_actions_for( instance_yml[:state] )
    File.open( instance_file, 'w' ) do |f|
      f << YAML.dump( instance_yml )
    end
    Instance.new( instance_yml )
  end