Dfyjkt

I'm really struggling to understand Contexts in Phoenix Elixir. I have three contexts, Auth (contains User.ex), Groups (Circle.ex), and Content (ShareMark.ex). Within each of those, there are schemas, users, circles, and sharemarks respectively.

I'm trying to figure out how to use the pre-provided create_circle outside of the Groups context. Is there something a context is analogous to in Ruby?

Within content_test.ex, I am trying to define the following

@valid_attrs %circle: Groups.create_circle(%name: "My test"), url: "google.com", title: "Google"

defmodule ShareMark.ContentTest do
 use ShareMark.DataCase

 alias ShareMark.Content
 use ShareMark.Groups
 describe "sharemarks" do
 alias ShareMark.Content.ShareMark
 @valid_attrs %circle: Groups.create_circle(%name: "Evan's test"), url: "google.com", title: "Google"
 @update_attrs %circle: Groups.create_circle(%name: "Mike's test"), url: "duckduckgo.com", title: "DuckDuckGo"
 @invalid_attrs %circle: Groups.create_circle(%name: "Bad test")

 def sharemark_fixture(attrs \ %) do
 :ok, sharemark =
 attrs
 |> Enum.into(@valid_attrs)
 |> Content.create_sharemark()

 sharemark
 end
 ...
end

Here is circle.ex

defmodule ShareMark.Groups.Circle do
 use Ecto.Schema
 import Ecto.Changeset

 schema "circles" do
 field :name, :string
 field :creator_id, :id
 many_to_many :members, ShareMark.Auth.User, join_through: "users_circles"
 has_many :sharemarks, ShareMark.Content.ShareMark

 timestamps()
 end

 @doc false
 def changeset(circle, attrs) do
 circle
 |> cast(attrs, [:name])
 |> validate_required([:name])
 end
end

But it is giving the following error:

** (CompileError) test/sharemark/content/content_test.exs:8: undefined function create_circle/1

Google is completely unhelpful, as Phoenix has so few questions asked about it. Sorry for such a novice question.

In your test you have this line:

use ShareMark.Groups

this should be an alias statement:

alias ShareMark.Groups

For starters, phoenix-framework does not force you to use Contexts, they're just a way of better organizing your code. This makes them slightly more confusing for beginners, compared to the File-Type First (FTF) structure of rails applications, but makes the code heirarchy much more easier to understand and manage in the long haul.

You can choose to use contexts or just put all modules together. Either way, whatever public functions you define are acessible from anywhere else in the app (as long as you use the correct module name to call them).

More resources on Contexts:

• Youtube: Chris McCord on Contexts
  


• Hexdocs: Phoenix Contexts
  


• Blog Post: Organizing Large React Apps
  _{(Not about Elixir, but still a good overview)}

Now on to your actual code, there are two problems with it.

First, as @Paweł mentioned, you need to alias your module or use the full name:

alias ShareMark.Groups

Second, you're calling Groups.create_circle in a module attribute (@value). Module attributes aren't like your regular "variables", they are resolved at compile-time. Meaning, in your case, they will try to write to the database before you even start your test suite.

To fix that, either move your initialization logic to your actual test or into ExUnit's setup/1 callback:

setup do
 %circle: Groups.create_circle(%name: "Test Circle"
end

test "something", %circle: circle do
 valid_attrs = %circle: circle, url: "google.com", title: "Google"
 # assert something
end