Stubbing sleep

sleepy_spec.rb

# example borrowed from Capybara.timeout

class Sleepy
  
  def self.do_this(seconds = 1, &block)
    start_time = Time.now
    result = nil

    until result
      return result if result = yield
      if (seconds - (Time.now - start_time)) <= 0
        raise "Timeout!"
      end

      sleep(0.5)
    end
  end
end

describe "sleepy" do

  before do
    Sleepy.stub!(:sleep)
  end
  
  it "should return the value of the block if the block returns a truthy value" do
    Sleepy.do_this { "hello" }.should == "hello"
  end
  
  it "should retry the block until the value is truthy" do
    count = 0
    Sleepy.do_this { count +=1; count == 5 ? count : nil }.should == 5
  end

  it "should raise an error if the block doesn't return truthy inside the timeout" do
    lambda do
      Sleepy.do_this(10) { false }
    end.should raise_error
  end

end