rails NoMethodError: undefined method " " for nil:NilClass

Question

我正在编写 Michael Hartl (chapter 9) 的 rails 教程。

我收到这个错误：

 Error:
UsersLoginTest#test_login_with_remembering:
NoMethodError: undefined method `FILL_IN' for nil:NilClass
    test/integration/users_login_test.rb:42:in `block in <class:UsersLoginTest>'

在chapter 8中添加了FILL-IN，直到第9章才出现任何问题。我尝试了很多，但我无法修复它。这是我的 UsersLoginTest class.

class UsersLoginTest < ActionDispatch::IntegrationTest

  def setup
    @user = users(:michael)
  end

  test "login with invalid information" do
    get login_path
    assert_template 'sessions/new'
    post login_path, session: { email: "", password: "" }
    assert_template 'sessions/new'
    assert_not flash.empty?
    get root_path
    assert flash.empty?
  end

  test "login with valid information followed by logout" do
       get login_path
    post login_path, session: { email: @user.email, password: 'password' }
    assert is_logged_in?
    assert_redirected_to @user
    follow_redirect!
    assert_template 'users/show'
    assert_select "a[href=?]", login_path, count: 0
    assert_select "a[href=?]", logout_path
    assert_select "a[href=?]", user_path(@user)
    delete logout_path
    assert_not is_logged_in?
    assert_redirected_to root_url
    # Simulate a user clicking logout in a second window.
    delete logout_path
    follow_redirect!
    assert_select "a[href=?]", login_path
    assert_select "a[href=?]", logout_path,      count: 0
    assert_select "a[href=?]", user_path(@user), count: 0
  end

  test "login with remembering" do
    log_in_as(@user, remember_me: '1')
    assert_equal assigns(:user).FILL_IN, FILL_IN
  end

  test "login without remembering" do
    log_in_as(@user, remember_me: '0')
    assert_nil cookies['remember_token']
  end
end

第 42 行是：

assert_equal assigns(:user).FILL_IN,FILL_IN

Answer 1

FILL_IN 在这种情况下是一个占位符。 Michael 希望您用正确的文本替换它。

Answer 2

错误显示 assigns(:user) 正在返回 nil。

assigns 测试控制器中设置的实例变量。这里的期望是您在控制器中为 @user 设置了一个值，并且当对其调用方法 FILL_IN 时它将等于 FILL_IN。解决 @user 成为 nil 的问题后，您需要实际填写这些占位符。

Answer 3

如果您在清单 8.62 中执行了 "login with remembering exercise"，则需要在清单 9.29 中使用 @user 实例变量。我花了一段时间才意识到这一点，所以它可能会帮助其他初学者在代码中看到 Shadwell 的建议：

sessions_controller.rb

class SessionsController < ApplicationController
  # ...

  def create
    @user = User.find_by(email: params[:session][:email].downcase)
    if @user && @user.authenticate(params[:session][:password])
      log_in @user
      params[:session][:remember_me] == '1' ? remember(@user) : forget(@user)
      redirect_back_or @user
    else
      flash.now[:danger] = 'Invalid email/password combination' # Flash.now designed for rendered pages, disappears at the next request.
      render 'new'
    end
  end

  # ...
end

users_login_test.rb

# ...

 test "login with remembering" do
    log_in_as(@user, remember_me: '1')
    assert_equal assigns(:user).remember_token, cookies['remember_token']
  end

# ...

公平地说，Michael Hartl 建议我们用 git 解决单独主题分支中的练习。

rails NoMethodError: undefined method " " for nil:NilClass

rails NoMethodError: undefined method " " for nil:NilClass

ruby-on-rails

nomethoderror

railstutorial.org