create new object in nested model

Hi I created nested models: tests-questions-answers

resources :tests do    resources :questions do         resources :answers     end   end   resources :questions   resources :answers

models: class Test < ActiveRecord::Base   has_many :questions   accepts_nested_attributes_for :questions, :reject_if => :all_blank

class Question < ActiveRecord::Base belongs_to :test   has_many :answers   accepts_nested_attributes_for :answers, :reject_if => :all_blank , :allow_destroy => true

to create new object for question i wrote in answers's _form: <%= render :partial => "questions/question", :collection=>@test.questions %>

the view - questions/question: <%= fields_for_question(question) do |q| %> <div class="question">    <%= q.label :question %><br/>    <%= q.text_field :question %> <div class="actions">     <%= q.submit %> </div> </div> <%end%>

question controler: def create @test = Test.find(params[:test_id])       @question = @test.questions.create(params[:question])

But when i click on submit button. it does nothing!

can anyone help me please?                         thanks

Take a look at these railscasts:

Thank you

But i have another problem:

How to use render(association.to_s.singularize , :f => builder) when the partial is in a diffrent folder ? in the view there are 3 folders: 'tests', 'questions', 'answers'. so in '_form' in folder-'question' when there is a call to- link_to_add_fields("Add Answer", test_form, :answers)

i get the error- missing partial 'tests/answer_fields'.

it need to be: - 'answers/answer_fields'

what i need to change?