require_relative '../../spec_helper'

require 'fiber'

describe "Fiber.current" do
  ruby_version_is "3.1" do
    it "is available without an extra require" do
      ruby_exe("print Fiber.current.class", options: '--disable-gems --disable-did-you-mean').should == "Fiber"
    end
  end

  it "returns the root Fiber when called outside of a Fiber" do
    root = Fiber.current
    root.should be_an_instance_of(Fiber)
    # We can always transfer to the root Fiber; it will never die
    5.times do
      root.transfer.should be_nil
      root.alive?.should be_true
    end
  end

  it "returns the current Fiber when called from a Fiber" do
    fiber = Fiber.new do
      this = Fiber.current
      this.should be_an_instance_of(Fiber)
      this.should == fiber
      this.alive?.should be_true
    end
    fiber.resume
  end

  it "returns the current Fiber when called from a Fiber that transferred to another" do
    states = []
    fiber = Fiber.new do
      states << :fiber
      this = Fiber.current
      this.should be_an_instance_of(Fiber)
      this.should == fiber
      this.alive?.should be_true
    end

    fiber2 = Fiber.new do
      states << :fiber2
      fiber.transfer
      flunk
    end

    fiber3 = Fiber.new do
      states << :fiber3
      fiber2.transfer
      states << :fiber3_terminated
    end

    fiber3.resume

    states.should == [:fiber3, :fiber2, :fiber, :fiber3_terminated]
  end
end