问题描述
results_controller.rb
class Api::V1::ResultsController < Api::V1::ApplicationController
before_action :devices
include DataHelper
def show
results = get_dr_results
render json: { data: results }
end
private
def get_dr_results
program_ids = method_defined_in_crucible_helper
end
end
module DataHelper
include Cruciblehelper
def method_missing(method_name,*args,&block)
if condition
do_something
else
super.method_missing(method_name,&block)
end
end
def respond_to_missing?
true
end
end
module CrucibleHelper
def method_defined_in_crucible_helper
end
end
现在在我的 rspec 中,我尝试模拟方法 method_defined_in_crucible_helper。
describe Api::V1::DrResultsController,type: :controller do
describe 'GET #show' do
before do
allow_any_instance_of(CrucibleHelper).to receive(:method_defined_in_crucible_helper) { [utility_program.id,utility_program2.id] }
end
context 'returns data' do
context 'returns expected events' do
it 'should return success response with expected events' do
get :show
expect(JSON.parse(response.body)).to eq(expected_response)
end
end
我要了
Failure/Error:
def respond_to_missing?
true
end
ArgumentError:
wrong number of arguments (given 2,expected 0)
# ./app/helpers/data_helper.rb:72:in `respond_to_missing?'
如果我注释掉 respond_to_missing?方法,然后我的规格执行正常。有人能帮我解决这个错误吗?
解决方法
Ruby Delegator#respond_to_missing?
是负责返回丢失的方法是否能够被对象处理的方法,它需要 2 个参数:missing method name
和选项 include_private
。
最佳做法是:always define respond_to_missing?
when overriding method_missing
。
但是我不喜欢你申请的方式,背后的原因是最小惊喜规则,看看:
class DataHelper
def method_missing(method_name,*args,&block)
if method_name.to_s.start_with?('delegate')
puts "a delegate method"
else
super
end
end
def respond_to_missing?(method_name,include_private = false)
true
end
end
d = DataHelper.new
d.respond_to?(:answer) # true
d.answer # `method_missing': undefined method `answer' ... SURPRISE
如您所见,d
响应他可以负责 answer
方法,但是在调用该方法时,会引发 method_missing
错误。
因此,您需要同时使 method_missing
和 respond_to_missing?
匹配:
class DataHelper
def method_missing(method_name,&block)
if can_handle?(method_name)
puts "a delegate method"
else
super
end
end
def respond_to_missing?(method_name,include_private = false)
return true if can_handle?(method_name)
super
end
private
def can_handle?(method_name)
method_name.to_s.start_with?('delegate')
end
end
d = D.new
d.respond_to?(:delegate_answer) # true
d.delegate_answer # delegate method
d.respond_to?(:answer) # false
d.answer # error