Data generation framework for Elixir.
In testing, sometimes it's useful to create records in the form of maps. Blacksmith makes it easy.
First, install Blacksmith:
In your mix.exs file, add the blacksmith dependency:
def deps do
[{:blacksmith, "~> 0.1"}]
endYou will also have to add :blacksmith to your application list:
def application do
[applications: applications(Mix.env)]
end
defp applications(:test), do: applications(:all) ++ [:blacksmith]
defp applications(_all), do: [:logger]Next, tell Blacksmith how to save one record, or many records:
defmodule Blacksmith.Config do
def save(model) do
MyRepo |> save(model)
end
def save_all(list_of_models) do
MyRepo |> save_all(list_of_models)
end
endNext, perhaps in test_helper for convenience or somewhere in lib for speed, register each of your new models with Forge. Use Faker for fake values, and sequences to maintain unique values:
defmodule Forge do
use Blacksmith
register :user,
name: Faker.Name.first_name,
email: Sequence.next(:email, &"test#{&1}@example.com"),
description: Faker.Lorem.sentence,
roles: [],
always_the_same: "string"
# this will create a user with roles set to [:admin]
register :admin,
[prototype: :user],
roles: ["admin"]
endNow you can create a user, generating all of the default values:
user = Forge.useror a saved user, with the name attribute overridden, and a new attribute of favorite_language:
user = Forge.saved_user
name: "Will Override",
favorite_language: "Elixir"or a list of 5 users
user = Forge.user_list 5or a saved list of 5 admins
admin = Forge.saved_admin_list repo, 5Create a list using a few common data elements:
Forge.having survey_id: some_survey.id, author: Forge.user do
question = Forge.question # will share the same survey id and user from above
endNext release: allow nesting of having blocks.
Blacksmith can be used easily with a database persistence library such as Ecto.
defmodule User do
use Ecto.Model
schema "users" do
field :name, :string
field :email, :string
end
endThe @save_one_function and @save_all_function attributes are used to delegate to your persistence layer. We delegate to Blacksmith.Config defined below. You'll also notice that we directly create a struct in register :user, that's because Ecto works with models built on structs instead of plain maps.
defmodule Forge do
use Blacksmith
@save_one_function &Blacksmith.Config.save/1
@save_all_function &Blacksmith.Config.save_all/1
register :user, %User{
name: "John Henry",
email: Sequence.next(:email, &"jh#{&1}@example.com")
}
endBlacksmith.Config defines the callback functions that delegate to the Ecto repository for persistence.
defmodule Blacksmith.Config do
def save(map) do
MyRepo.insert(map)
end
def save_all(list) do
Enum.map(list, &MyRepo.insert/1)
end
endForge.saved_user will generate a User model that have been inserted in the database backed by MyRepo.