ruby on rails - NameError: uninitialized constant ApplicationHelperTest::Fill_IN -

i error message when add last test in code ruby on rails tutorial, listing 6.11 , 6.12 , run bundle exec rake test listing 6.13 running linux xubuntu

1) error: applicationhelpertest#test_full_title_helper: nameerror: uninitialized constant applicationhelpertest::fill_in test/helpers/application_helper_test.rb:5:in `block in '

when remove email validation test passes.

test/models/user_test.rb

require 'test_helper'  class usertest < activesupport::testcase   def setup     @user = user.new(name: "example user", email: "user@example.com")   end    test "should valid"     assert @user.valid?   end    test "name should present"     @user.name = ""     assert_not @user.valid?   end    test "email should present"     @user.email = "     "     assert_not @user.valid?   end   end 

app/models/user.rb

class user < activerecord::base   validates :name,  presence: true   validates :email, presence: true end 

i think must have application helper. code in helper:

require 'test_helper'  class applicationhelpertest < actionview::testcase    test "full title helper"     assert_equal full_title,         fill_in     assert_equal full_title("help"), fill_in   end end 

it's because test trying constant called fill_in, doesn't exist. tutorial asking replace fill_in proper values.