runs_in.rb

module Bench
  module Matchers
    class RunsIn #:nodoc:
      def initialize(receiver=nil, &block)
        @receiver = receiver
        # Placeholder
      end
      
      def matches?(event_proc)
        raise_block_syntax_error if block_given?
        
        before = Time.now
        event_proc.call
        after = Time.now
        
        return (after - before) < @receiver
      end
      
    end
    
    def run_in(receiver=nil, &block)
      Matchers::RunsIn.new(receiver, &block)
    end
  end
end

runs_in_spec.rb

describe "Bench" do
  it "runs in under 2.5 seconds" do
    lambda { sleep(1) }.should run_in(2.5.seconds)
  end
  
  it "fails to run in under 2.5 seconds" do
    lambda { sleep(2.6) }.should_not run_in(2.5.seconds)
  end
end

spec_helper

Spec::Runner.configure do |config|
  config.include(Bench::Matchers)
end