tester_elf.rb

#!/usr/bin/env ruby

# tester_elf simply autoruns a ruby test file when you save it.
# As dumb as it gets, but sometimes convenient.
# 
# Usage:
# 1) Place it in your "script" dir
# 2) chmod +x script/tester_elf
# 3) script/tester_elf
# Stop using Ctrl/Cmd + C
#
# Based on restarter script by Jonathan Penn (http://www.wavethenavel.com).
# Tweaked around by Maxim Chernyak (http://mediumexposure.com)

POLL_DIRECTORIES = %w(test/unit test/functional)
POLL_TIME = 0.9
RUN_WITH = "ruby -Itest"

class TesterElf
  def initialize(options = {})
    @dirs       = options[:dirs]      || %w(test/unit test/functional)
    @interval   = options[:interval]  || 0.9
    @command    = options[:command]   || 'ruby -Itest'
    @states     = {}
  end  
  
  def work!
    Dir.chdir(File.join(File.dirname(__FILE__), '..'))
    $stderr.puts "Tester Elf is at your service... Checking files in #{@dirs.join(', ')} every #{@interval} seconds."    
    
    processes = []
    Signal.trap(0) do
      processes.map{|p| Process.kill("INT", p)}
    end
    
    Signal.trap("INT") do
      $stderr.puts "Shutting down tester_elf" 
      exit
    end
    
    check_for_changes
    
    loop do
      sleep @interval
      changes = check_for_changes
      unless changes.empty?
        $stderr.puts emphasized("Running test...#{changes.inspect}")        
        processes.map{|p| Process.kill("INT", p)}
        processes = changes.collect do |path| 
          fork { exec("#{@command} #{path}") }
        end
      end
    end    
  end
  
  
  private 
  def emphasized(m)
    "\e[1;1m\e[41m \e[0m \e[1;1m\e[1m #{m} \e[0m"
  end
  
  def check_for_changes
    changes = []
    Dir[*@dirs.map{|i|i+"/**/*"}].each do |file|
      unless File.symlink?(file)
        new_time = File.stat(file).mtime
        if @states[file] != new_time
          @states[file] = new_time
          changes << file
        end
      end
    end
    changes
  end
end

elf = TesterElf.new(:dirs => POLL_DIRECTORIES, :interval => POLL_TIME, :command => RUN_WITH)
elf.work!