How to correctly define a fabricator that ex_machina's `params_for` recognises? - testing

Question

I started on a test that should verify that the fabricated objects are valid.
But even though I have defined a practitioner_factory, it does not find it.
Any idea why?
practitioner_factory! works when I manually run it from iex.
1 defmodule Booking.PractitionersTest do
2 use ExUnit.Case, async: true
3 use Booking.DataCase
4 use ExMachina.Ecto
5 alias Ecto.Changeset
6 alias Booking.Factory
7
22 test "is valid from the factory" do
23 new_practitioner = params_for(:practitioner)
24 changeset = Practitioner.changeset(Practitioner, new_practitioner)
25 assert changeset.valid?
26 end
It crashes with the following stack trace:
1) test practitioners is valid from the factory (Booking.PractitionersTest)
test/booking/practitioners_test.exs:22
** (ExMachina.UndefinedFactoryError) No factory defined for :practitioner.
Please check for typos or define your factory:
def practitioner_factory do
...
end
code: new_practitioner = params_for(:practitioner)
stacktrace:
(ex_machina 2.7.0) lib/ex_machina.ex:243: ExMachina.build/3
(ex_machina 2.7.0) lib/ex_machina/ecto.ex:127: ExMachina.Ecto.params_for/3
test/booking/practitioners_test.exs:23: (test)
Here's my lib/booking/factory.ex
1 defmodule Booking.Factory do
2 # with Ecto
3 use ExMachina.Ecto, repo: Booking.Repo
4
5 alias Booking.Practitioners.Practitioner
6 alias Booking.Products.Product
7 alias Booking.Repo
8
9 def practitioner_factory do
10 %Practitioner{
11 first_name: Faker.Person.first_name(),
12 last_name: Faker.Person.last_name()
13 }
14 end
23 def practitioner_factory! do
24 practitioner_factory()
25 |> Repo.insert()
26 end

Answer 1

Looking at the path where you have defined the factory it looks like it's not in the test folder. If you don't need to use the factory in other environments, you can add it inside test/support so that it is only compiled in the test environment.
Also, be sure to start the application in your test/test_helper.exs before ExUnit.start, using:
{:ok, _} = Application.ensure_all_started(:ex_machina)
Looking at your test file, you have:
1 defmodule Booking.PractitionersTest do
2 use ExUnit.Case, async: true
3 use Booking.DataCase
4 use ExMachina.Ecto
5 alias Ecto.Changeset
6 alias Booking.Factory
...
23 new_practitioner = params_for(:practitioner)
As you're not doing something like Factory.params_for(:practitioner) (from the alias Booking.Factory), you need to do something like import Booking.Factory in line 6, otherwise that factory is not defined in your test file.
Also, you probably don't need line 4 use ExMachina.Ecto as that is already defined in line 3 of lib/booking/factory.ex.