run only edited test method by watchr

gistfile1.rb

require 'diff/lcs'
require 'diff/lcs/string'
require 'digest/md5'
require 'fileutils'
require 'shellwords'

@project_name = "hogehoge"

watch( 'test/test_.*\.rb' )  {|md| system("rake test") }

# .....

watch( 'test/integration/(.*)_test\.rb' ) do |md|
  run_test_by_diff("test/integration/#{md[1]}_test.rb")
end

def run_test_by_diff(file)
  snapshot = "/tmp/.watchr.#{@project_name}-#{Digest::MD5.hexdigest(file) }"
  cmd = %|ruby -I"lib:test" #{file.shellescape}|
  cmd_plus = ""

  if File.exist?(snapshot)
    diff_result = File.read(snapshot).diff(File.read(file))
    if diff_result.empty?
      puts "FILE NOT CHANGED!!"
      return
    end

    test_methods = get_test_methods(file, diff_result)
    # if all changes looks like inside TEST
    unless test_methods.include?(nil)
      if test_methods.size > 1
        methods_regex = "/^(#{test_methods.join("|")})$/"
        cmd_plus = " -n #{methods_regex.shellescape}"
      else
        cmd_plus = " -n #{test_methods.first.shellescape}"
      end
    end
  end

  FileUtils.cp file, snapshot
  cmd += cmd_plus
  puts "call: #{cmd}"
  system(cmd)
end

def get_test_methods(file, diff_result)
  ret = []
  all_lines = File.read(file).lines.to_a
  diff_result.each do |r|
    ret << get_test_method(all_lines, r)
  end

  ret.uniq
end

def get_test_method(lines, r)
  size_at = 0
  line_at = 0

  lines.each do |l|
    size_at += l.size
    line_at += 1
    if size_at >= r[0].position
      break
    end
  end

  i = line_at
  while (i > 0) do
    i -= 1
    # test "****" do
    if lines[i] =~ /\A\s+test\s+(["']|%\|)(.+?)(["']|\|)\s+do\s*\z/
      return "test_#{$2}"
    end

    # def test_**** do
    if lines[i] =~ /\A\s+def\s+(test_.+?)\z/
      return $1
    end

    # def ****
    if lines[i] =~ /\A\s+def\s+/
      return nil
    end
  end

  nil
end