sessions: remove nonexistent GET /session route.

config/routes.rb

@@ -255,10 +255,8 @@ Rails.application.routes.draw do
       get :labels
     end
   end
-  resource :session do
-    collection do
-      get :sign_out
-    end
+  resource :session, only: [:new, :create, :destroy] do
+    get :sign_out, on: :collection
   end
   resource :source, :only => [:show]
   resources :tags do

test/functional/sessions_controller_test.rb

@@ -30,5 +30,13 @@ class SessionsControllerTest < ActionDispatch::IntegrationTest
         assert_nil(session[:user_id])
       end
     end
+
+    context "sign_out action" do
+      should "clear the session" do
+        get_auth sign_out_session_path, @user
+        assert_redirected_to posts_path
+        assert_nil(session[:user_id])
+      end
+    end
   end
 end