spec/ruby/library/fiber/transfer_spec.rb


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require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../../../shared/fiber/resume', __FILE__)

with_feature :fiber_library do
  require 'fiber'

  describe "Fiber#transfer" do
    it_behaves_like :fiber_resume, :transfer
  end

  describe "Fiber#transfer" do
    it "transfers control from one Fiber to another when called from a Fiber" do
      fiber1 = Fiber.new { :fiber1 }
      fiber2 = Fiber.new { fiber1.transfer; :fiber2 }
      fiber2.resume.should == :fiber1
    end

    it "returns to the root Fiber when finished" do
      f1 = Fiber.new { :fiber_1 }
      f2 = Fiber.new { f1.transfer; :fiber_2 }

      f2.transfer.should == :fiber_1
      f2.transfer.should == :fiber_2
    end

    it "can be invoked from the same Fiber it transfers control to" do
      states = []
      fiber = Fiber.new { states << :start; fiber.transfer; states << :end }
      fiber.transfer
      states.should == [:start, :end]

      states = []
      fiber = Fiber.new { states << :start; fiber.transfer; states << :end }
      fiber.resume
      states.should == [:start, :end]
    end

    it "can transfer control to a Fiber that has transferred to another Fiber" do
      states = []
      fiber1 = Fiber.new { states << :fiber1 }
      fiber2 = Fiber.new { states << :fiber2_start; fiber1.transfer; states << :fiber2_end}
      fiber2.resume.should == [:fiber2_start, :fiber1]
      fiber2.transfer.should == [:fiber2_start, :fiber1, :fiber2_end]
    end

    it "raises a FiberError when transferring to a Fiber which resumes itself" do
      fiber = Fiber.new { fiber.resume }
      lambda { fiber.transfer }.should raise_error(FiberError)
    end
  end
end