Michael Hartl's Rails 5 tutorial chapter 10, listing 10.62, error in integration test for delete links and destroying user

Doing last exercise of chapter 10, wild NoMethodError has appeared in listing 10.62 test

test/integration/users_index_test.rb

require 'test_helper'

class UsersIndexTest < ActionDispatch::IntegrationTest

  def setup
    @admin     = users(:michael)
    @non_admin = users(:archer)
  end

  test "index as admin including pagination and delete links" do
    log_in_as(@admin)
    get users_path
    assert_template 'users/index'
    assert_select 'div.pagination'
    first_page_of_users = User.paginate(page: 1)
    first_page_of_users.each do |user|
      assert_select 'a[href=?]', user_path(user), text: user.name
      unless user == @admin
        assert_select 'a[href=?]', user_path(user), text: 'delete'
      end
    end
    assert_difference 'User.count', -1 do
      delete user_path(@non_admin)
    end
  end

  test "index as non-admin" do
    log_in_as(@non_admin)
    get users_path
    assert_select 'a', text: 'delete', count: 0
  end
end

test error

ERROR["test_index_as_admin_including_pagination_and_delete_links", UsersIndexTest, 0.8833864140324295]
 test_index_as_admin_including_pagination_and_delete_links#UsersIndexTest (0.88s)
NoMethodError:         NoMethodError: undefined method `email' for nil:NilClass
            test/test_helper.rb:31:in `log_in_as'
            test/integration/users_index_test.rb:11:in `block in <class:UsersIndexTest>'

Any ideas what could be missed here? Many thanks!