title: NameError: uninitialized constant ApplicationHelperTest::Fill_IN
body: <p>I get this error message when I add the last test in this code from Ruby on Rails Tutorial, from listing 6.11 and 6.12 and then run the bundle exec rake test Listing 6.13 I am running Linux Xubuntu</p>
  
  <blockquote>
    <p>1) Error:
        ApplicationHelperTest#test_full_title_helper:
        NameError: uninitialized constant ApplicationHelperTest::FILL_IN
            test/helpers/application_helper_test.rb:5:in `block in '</p>
  </blockquote>
  
  <p>When I remove the email validation the test passes. </p>
  
  <p><strong><em>test/models/user_test.rb</em></strong></p>
  
  <pre><code>require 'test_helper'
  
  class UserTest &lt; ActiveSupport::TestCase
    def setup
      @user = User.new(name: "Example User", email: "user@example.com")
    end
  
    test "should be valid" do
      assert @user.valid?
    end
  
    test "name should be present" do
      @user.name = ""
      assert_not @user.valid?
    end
  
    test "email should be present" do
      @user.email = "     "
      assert_not @user.valid?
    end  
  end
  </code></pre>
  
  <p><strong><em>app/models/user.rb</em></strong></p>
  
  <pre><code>class User &lt; ActiveRecord::Base
    validates :name,  presence: true
    validates :email, presence: true
  end
  </code></pre>
  
  <p>I think it must have something to do with the Application Helper. this is the code in the helper:</p>
  
  <pre><code>require 'test_helper'
  
  class ApplicationHelperTest &lt; ActionView::TestCase
  
    test "full title helper" do
      assert_equal full_title,         FILL_IN
      assert_equal full_title("Help"), FILL_IN
    end
  end
  </code></pre>