# File activesupport/lib/active_support/testing/isolation.rb, line 62
def run_in_isolation(&blk)
  require "tempfile"

  if ENV["ISOLATION_TEST"]
    yield
    File.open(ENV["ISOLATION_OUTPUT"], "w") do |file|
      file.puts [Marshal.dump(self.dup)].pack("m")
    end
    exit!
  else
    Tempfile.open("isolation") do |tmpfile|
      ENV["ISOLATION_TEST"]   = self.class.name
      ENV["ISOLATION_OUTPUT"] = tmpfile.path

      load_paths = $-I.map {|p| "-I\"#{File.expand_path(p)}\"" }.join(" ")
      %x`#{Gem.ruby} #{load_paths} #{$0} #{ORIG_ARGV.join(" ")}`

      ENV.delete("ISOLATION_TEST")
      ENV.delete("ISOLATION_OUTPUT")

      return tmpfile.read.unpack("m")[0]
    end
  end
end