Rspec received unexpected message :[] with - json

Question

I write a mapper which matches attributes received from facebook and set them to my model.
class Mapper::FacebookUser
def initialize (user, facebook_user)
#user = user
#facebook_user = facebook_user
end
def name
#user.name = #facebook_user['name'] if #facebook_user['name'] rescue false
end
end
The response from Facebook is something like this: (JSON)
{
"name": "Jo Doe"
}
And my user_spec is that:
require 'spec_helper.rb'
describe Mapper::FacebookUser do
before(:each) do
#facebook_user = double("FacebookUser")
#user = User.new
end
it 'should map name to name' do
#facebook_user.stub(:name).and_return("User Name")
Mapper::FacebookUser.new(#user, #facebook_user).name
#user.name.should eq("User Name")
end
end
RSpec::Mocks::MockExpectationError: Double "Facebook" received
unexpected message :[] with ("name")
I tried the following:
#facebook_user.stub(:name).and_return("User Name")
#facebook_user.stub("name").and_return("User Name")
#facebook_user.stub(:[]).and_return({name: "User Name"})
#facebook_user.stub(:[]).and_return({name: "User Name"}.to_json)
only this one works, but I am quite sure, that's not the way:
#facebook_user.stub(:[]).and_return("User Name")
What is wrong with my approach?
How can I get my test working?
many thanks
I use rspec:
rspec (2.14.1)
rspec-core (2.14.7)
rspec-expectations (2.14.4)
rspec-mocks (2.14.4)
rspec-rails (2.14.0)

Answer 1

First, you're not obviously using #facebook_event in your model, so I'm not sure you're stubbing it. If you want to stub the object/method you are using in your name method, you'd need to stub the :[] method on the #facebook_user object you're passing in on your new call. The reason you're getting the error you're getting is because your not stubbing that method.
I assume the one approach you tried with the #facebook_event stub is working because the real Mapper::FacebookUser#[] method calls that object in that way.

Answer 2

My approach is now
I hope this helps someone
facebook_user = { "name": "Jo Doe" }
class Mapper::FacebookUser
def initialize (user, facebook_user={})
#user = user # AR model
# allows ['key'] or [:keys]
#facebook_user = facebook_user.with_indifferent_access
end
def name
#user.name = #facebook_user.dig('name') # sets to nil if not present (works also with chains) >= Ruby 2.3
end
end
require 'spec_helper.rb'
describe Mapper::FacebookUser do
before(:each) do
#user = User.new
#facebook_user = {}
end
it 'should map name to name' do
#facebook_user['name']
Mapper::FacebookUser.new(#user, #facebook_user).name
#user.name.should eq("User Name")
end
end