Uninitialized Constant when adding helper module to Model Test

I'm trying to do something fairly simple - add a module with helper methods to a Model test, but i keep getting the following error

uninitialized constant NeighborhoodTest::NeighboorhoodTestHelper

The module is located in test/helpers/neighborhood_test_helper.rb

module NeighborhoodTestHelper

  def create_polygon
    points = self.geolocate
    boundary = Geokit::Polygon.new(points)
  end
   .
   .
end

Per the recommendation in this SO answer, did the following inside test/models/neighborhood_test.rb:

require 'test_helper'
require 'helpers/neighborhood_test_helper'


class NeighborhoodTest < ActiveSupport::TestCase
  include NeighboorhoodTestHelper

  def setup
    @crime = crimes(:arrest)
    @neighborhood = neighborhoods(:one)
  end

   test "neighborhood should contain crime" do
     neighborhood_boundary = @neighborhood.create_polygon
     crime_location = @crime.geolocate
     assert neighborhood_boundary.contains?(crime_location)
   end
end

I also tried this SO that didn't work. Anyone know why this approach doesnt work in Models?