post command not rendering data in Rspec - ruby-on-rails

Question

I have defined a controller Add. In controller i have defined a function (add_params)
def add_values
ans = params[:first_element] + params[:second_element]
render :json => {:result => ans}.to_json
end
in routes file i have declared post :add_params
if i call curl -X POST -H "Content-Type:application/json" -d '{"first_element" : 3, "second_element" :2}' http://localhost:8000/add/add_values it return {"result":5}
but when i tried to test in Rspec as
describe AddController, :type => :request do
it "must return 5" do
post "http://localhost:8000/add/add_values", {"first_element" : 3, "second_element" :2}.to_json
expect(JSON.parse(response.body)["result"]).to eq "5"
end
end
it gives error as
Failure/Error: expect(response["result_is"]).to eq 5
expected: 5
got: nil
(compared using ==)
# ./spec/controller/add_controller_spec.rb:67:in `block (2 levels) in <top (required)>'
i am using rails 3.2.16 , ruby 2.1.5 , rspec 3.0.0

Answer 1

Is pretty weird that you receive
Failure/Error: expect(response["result_is"]).to eq 5
if your expectation is
expect(JSON.parse(response.body)["result"]).to eq "5"
the parameters of expect function are different one each other.
You should receive an error like this
Failure/Error: expect(JSON.parse(response.body)["result_is"]).to eq "5"
Are you sure your expectation is not
expect(response["result_is"]).to eq 5
?