Grape api (rails) - uninitialized constant Endpoints::TodoAPI (NameError)

I'm using grape to create an api in rails. The project is still pretty fresh but I've hit a blocking point so far with my routes.

I added an test endpoint to see if my versions were working together and they were

my config/routes.rb file

Rails.application.routes.draw do
  mount Root => '/'
end

my app/api/root.rb file

require "grape"

class Root < Grape::API
  format :json

  mount Test::API
end

my app/api/test/api.rb file

require "grape"

module Test
  class API < Grape::API

    get :world do
      {
        "response"=>"hello world!",
        "name"=>"it is i"
      }
    end
  end
end

and my api/test/api_spec.rb file

require 'rails_helper'

describe 'Endpoints' do
  context 'when the endpoint "world" is hit' do
    context 'the response' do
      let(:res) { JSON.parse(response.body)['response'] }

      it 'returns hello world' do
        get '/world'
        expect(res).to eq 'hello world!'
      end
    end
  end
end

All of this worked perfectly well, so I tried adding another mount to my app/api/root.rb file

require "grape"

class Root < Grape::API
  format :json

  mount Test::API
  mount Endpoints::TodoAPI
end

and my app/api/endpoints/todoapi.rb file

require "grape"

module Endpoints
  class TodoAPI < Grape::API

  end
end

when I tried to run my api/test/api_spec.rb file, I suddenly started getting an error

Failure/Error: mount Endpoints::TodoAPI


NameError:

  uninitialized constant Endpoints::TodoAPI


    mount Endpoints::TodoAPI

                   ^^^^^^^^^

  Did you mean?  Endpoints::Todoapi

I tried to make the TodoAPI look exactly like the api file, and comment out api's mount but I keep getting the same error.

Your class name is wrong class TodoAPI for file name todoapi.rb should be

class Todoapi

hence the

Did you mean? Endpoints::Todoapi statement.

Class names in ruby follow strict naming conventions and follow the snake case file naming with matching camel case class names principle where words are separated by underscores in the file name then the corresponding words in the class name start with a capital letter

e.g. a file containing the class definition of Class ToDoApi would have live inside a file named to_do_api.rb