Rspec testing API versioning - ruby-on-rails

Question

I'm working with a web api in rails 4.1.8 and i'm doing some testing but always is returning me
Failure/Error: post '/v1/users', subdomain: 'api', user: #user.to_json, format: :json
ActionController::UrlGenerationError:
No route matches {:action=>"/v1/users", :controller=>"api/v1/users", :format=>:json, :subdomain=>"api", :user=>"JSON_OBJ"}
but if i test it in the browser with Advance Rest Console it works, i don't know what i'm doing wrong
here is me code
routes.rb
namespace :api, path: '/', constraints: {subdomain: 'api'}, defaults: { format: :json } do
namespace :v1 do
with_options except: [:edit, :new] do |except|
except.resources :users do
collection do
post 'login'
post 'showme'
end
end
except.resources :products
except.resources :locations
end
end
end
and my controller spec
module API
module V1
describe UsersController do
before do
request.host = "api.example.com"
expect({:post => "http://#{request.host}/v1/users"}).to(
route_to( controller: "api/v1/users",
action: "create",
subdomain: 'api',
format: :json
)
) # => PASS
# token expectations
#auth_token = allow(JWT::AuthToken).to(
receive(:make_token).and_return("mysecretkey")
)
expect(JWT::AuthToken.make_token({}, 3600)).to eq("mysecretkey")
end
describe "Create User" do
before(:each) do
#user = FactoryGirl.attributes_for :user
end
it 'should return a token' do
post '/v1/users', subdomain: 'api', user: #user.to_json, format: :json # Error
response_body = JSON.parse(response.body, symbolize_names: true)
expect(response_body['token']).to eql "mysecretkey"
end
end
end
end
end
rake routes
login_api_v1_users POST /v1/users/login(.:format) api/v1/users#login {:format=>:json, :subdomain=>"api"}
showme_api_v1_users POST /v1/users/showme(.:format) api/v1/users#showme {:format=>:json, :subdomain=>"api"}
api_v1_users GET /v1/users(.:format) api/v1/users#index {:format=>:json, :subdomain=>"api"}
POST /v1/users(.:format) api/v1/users#create {:format=>:json, :subdomain=>"api"}
api_v1_user GET /v1/users/:id(.:format) api/v1/users#show {:format=>:json, :subdomain=>"api"}
PATCH /v1/users/:id(.:format) api/v1/users#update {:format=>:json, :subdomain=>"api"}
PUT /v1/users/:id(.:format) api/v1/users#update {:format=>:json, :subdomain=>"api"}
DELETE /v1/users/:id(.:format) api/v1/users#destroy {:format=>:json, :subdomain=>"api"}

Answer 1

As described in http://api.rubyonrails.org/classes/ActionController/TestCase/Behavior.html which is referenced in https://www.relishapp.com/rspec/rspec-rails/docs/controller-specs, the first argument to post in your RSpec example is the name of the controller method to be called (i.e. :create in your case), not the route to that method.