Fake Time.now and Time.zone.now

gistfile1.rb

$start = Time.now - 1.month # this time last month
class Time
  class << Time
    def new
      $start
    end
    def now
      Time.new
    end
  end
end

class TimeWithZone
  class << TimeWithZone
    def new
      $start
    end
    def now
      Time.new
    end
  end
end