Stub some time for Rails, not in tests

stub_time.rb

# Lifting from http://stackoverflow.com/questions/714042/unit-testing-code-which-gets-current-time
# mostly, but adding a non-block version.
#
# Toss this into config/initializers/stub_time.rb and set a 
# time at the bottom of the file.
#
# Danger Will Robinson, Danger!
#
require 'time'

class Time
  def self.metaclass
    class << self; self; end
  end

  def self.is(point_in_time)
    new_time = case point_in_time
      when String then Time.parse(point_in_time)
      when Time then point_in_time
      else raise ArgumentError.new("argument should be a string or time instance")
    end
    class << self
      alias old_now now
    end
    metaclass.class_eval do
      define_method :now do
        new_time
      end
    end
    if block_given?
      yield
      class << self
        alias now old_now
        undef old_now
      end
    end
  end
end

# Time.is '2011-11-01'