Ruby error: "Symbol as array index"

Question

I am writing a spec for the create method of a controller :

describe "POST create" do

    it "should create an adtag with valid params" do
      campaign = Campaign.make

      campaign_attributes = Hash.new
      campaign_attributes[:adtag_attributes] = Hash.new
      campaign_attributes[:adtag_attributes][:code] = "<h1>Sample code</h1>"

      post 'create', { :id => campaign.id, :campaign => campaign_attributes }
    end

end

But when I run it, I get the error "Symbol as array index" in the controller, when it tries to process this code :

params[:campaign][:adtag_attributes].each_with_index do |attributes,index|
  # some code
end

Any idea ? Thanks

EDIT 1:

I haven't written the controller, but it works with manual testing. The view that calls my controller has this code:

fields_for 'campaign[adtag_attributes][]', adtag do |adtag_form|

Maybe my spec isn't good ?

EDIT 2:

Problem resolved thanks to Rishav's answer. I didn't understand that in the view, campaign[adtag_attributes][] means that campaign[adtag_attributes] is an Array.

So I just replaced

campaign_attributes = Hash.new
campaign_attributes[:adtag_attributes] = Hash.new
campaign_attributes[:adtag_attributes][:code] = "<h1>Sample code</h1>"

by

campaign_attributes = Hash.new
campaign_attributes[:adtag_attributes] = Array.new
campaign_attributes[:adtag_attributes] << { :code => "<h1>Sample code</h1>" }

and it worked out.

Answer 1

params[:campaign][:adtag_attributes] is a hash not an array, so when it runs "each_with_index" method on the hash it sees ":code" symbol as the index and throws that error.

You can just do this

 params[:campaign][:adtag_attributes].each do |key,value|
    #some code
 end

just change to following in the test

params[:campaign][:adtag_attributes] = []
params[:campaign][:adtag_attributes] << somedata

hopefully this works