class ActiveSupport::Testing::SimpleStubs

def initialize
  @stubs = {}
end

def stub_object(object, method_name, &block)
  key = [object.object_id, method_name]
  if stub = @stubs[key]
    unstub_object(stub)
  end
  new_name = "__simple_stub__#{method_name}"
  @stubs[key] = Stub.new(object, method_name, new_name)
  object.singleton_class.send :alias_method, new_name, method_name
  object.define_singleton_method(method_name, &block)
end

def unstub_all!
  @stubs.each_value do |stub|
    unstub_object(stub)
  end
  @stubs = {}
end

def unstub_object(stub)
  singleton_class = stub.object.singleton_class
  singleton_class.send :undef_method, stub.method_name
  singleton_class.send :alias_method, stub.method_name, stub.original_method
  singleton_class.send :undef_method, stub.original_method
end