Unable to use subject/let syntax with Phoenix Framework's ConnTest

[Marcin Lewandowski]

I am using pavlov to test Phoenix Framework controllers.

Consider the following example:

defmodule MyApp.UserTest do
  use MyApp.ConnCase, async: true # default ConnCase generated by Phoenix 
  use Pavlov.Case, async: true
  import Pavlov.Syntax.Expect

  let(:base_url) do
    "/api/user" 
  end

  describe "POST (base_url)" do
    context "if no Authorization header was passed" do
      @endpoint MyApp.Endpoint

      subject do
        conn() |> post base_url
      end      

      it "returns status code of 401 Unauthorized" do 
        expect subject.status |> to_eq 401
      end
    end
  end
end

It will end up with

** (CompileError) test/controllers/user_test.exs:52: function conn/0 undefined
    (stdlib) lists.erl:1337: :lists.foreach/2
    test/controllers/user_test.exs:48: (module)
    test/controllers/user_test.exs:47: (module)

If I add module names:

defmodule MyApp.UserTest do
  use MyApp.ConnCase, async: true # default ConnCase generated by Phoenix 
  use Pavlov.Case, async: true
  import Pavlov.Syntax.Expect

  let(:base_url) do
    "/api/user" 
  end

  describe "POST (base_url)" do
    context "if no Authorization header was passed" do
      @endpoint MyApp.Endpoint

      subject do
        Phoenix.ConnTest.conn() |> Phoenix.ConnTest.post base_url # Here we add module names
      end      

      it "returns status code of 401 Unauthorized" do 
        expect subject.status |> to_eq 401
      end
    end
  end
end

it will end up with the following error:

** (CompileError) nofile:52: you must require Phoenix.ConnTest before invoking the macro Phoenix.ConnTest.post/2
    (elixir) expanding macro: Kernel.|>/2
    nofile:52: :"Elixir.MyApp.UserControllerTest.POST (base_url).if no Authorization header was passed".subject/0
    (elixir) lib/module.ex:360: Module.eval_quoted/4
    (elixir) lib/enum.ex:543: anonymous fn/3 in Enum.each/2
    (elixir) lib/enum.ex:1275: anonymous fn/3 in Enum.reduce/3
    (elixir) lib/stream.ex:717: Stream.do_transform_each/3

The same happens if I try to use let.

That makes let/subject syntax useless for testing Phoenix controllers.

let/subject IMO should be always evaluated in the scope of the calling function.