《Ruby on Rails教程》8.2.1章节测试报错求助

Hey there! Let's work through this test error you're stuck on—trust me, I've been there when you've combed through code a dozen times and still can't spot the issue.

First, let's break down the error:

NameError: undefined local variable or method `users_new_url' for #UsersControllerTest:0x00000006e953f8

This means your test is trying to use a named route called users_new_url, but Rails doesn't recognize it. Here's why and how to fix it:

The Root Cause #

Rails follows strict conventions for RESTful named routes. For the "new" action (which renders the signup form), the correct named route is singular—new_user_url (or new_user_path for relative paths), not the plural users_new_url you're currently using.

Step-by-Step Fixes #

1. Update your test file
   Open test/controllers/users_controller_test.rb and find the line where you're calling users_new_url. Replace it with the correct route:

   # Before (broken)
   get users_new_url
   
   # After (fixed)
   get new_user_url
   # Or use the path version (common in tests)
   get new_user_path
   

2. Verify your routes are set up correctly
   Check your config/routes.rb file—you should have the RESTful resource route for users, which auto-generates all the correct named routes:

   resources :users
   

   To confirm, run this command in your terminal to list all available routes:

   rails routes
   

   Look for a line like this (it confirms the new_user route exists):

   new_user GET    /users/new(.:format)    users#new
   

3. Double-check other files (just in case)
   If you still run into issues, do a quick scan of your users/new.html.erb view or users_controller.rb to make sure you didn't accidentally use users_new_url there too. But based on the error message, the problem is definitely in your controller test.

Quick Tip for Future Reference #

Rails' RESTful route naming follows a pattern:

• Collection actions (index, create) use plural: users_path, users_url
• Single-resource actions (new, show, edit, update, destroy) use singular: new_user_path, user_path(@user)

That should get your test passing! Let me know if you hit any other snags.

内容的提问来源于stack exchange，提问作者Mia Genovese