You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: test_scheduler.rb
    path of file: ./repos/ruby/test/fiber
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
require 'test/unit'
require_relative 'scheduler'

class TestFiberScheduler < Test::
    
  def test_fiber_without_scheduler
    # Cannot create fiber without scheduler.
    assert_raise RuntimeError do
      Fiber.schedule do
      end
    end
  end