Temporarily Overriding A Method in Ruby

test.rb

module Count
  def fake_count
    words.count + 500
  end
end

class Thing
  def words
    %w(one two three)
  end
  def count
    words.count
  end
end

def assert(value)
  raise "Assertion failed" unless value == true
end

thing = Thing.new
assert thing.count == 3
puts thing.count

class Thing
  include Count
  alias_method :real_count, :count
  alias_method :count, :fake_count
end

thing = Thing.new
assert thing.count == 503
puts thing.count

class Thing
  alias_method :count, :real_count
end

thing = Thing.new
assert thing.count == 3
puts thing.count