Documented here: GitHub - phoenixframework/phoenix_ecto: Phoenix and Ecto integration with support for concurrent acceptance testing · GitHub

@josevalim Thanks for the quick response, that was very helpful! I’m surprised Hound’s README doesn’t have a link to it. However, I’m still struggling to get this to work the way I think it should be.

I’ve got two tests, and when ran individually, they take ~15 seconds each (or ~30 seconds with mix test --only integration). After I added async: true I can see two Chrome browsers starting off, but strangely the total time with the async options and changes is still ~30 seconds, same as before, which seems wrong.

How could this be, is there something I’m missing? I followed the guide in the link carefully, and only made 1 change in the setup of my IntegrationCase file, due to an error:

defmodule MyApp.Web.IntegrationCase do
  use ExUnit.CaseTemplate

  using do
    quote do
      use Hound.Helpers
      import MyApp.Web.Router.Helpers
      import MyApp.Web.IntegrationCase

      @endpoint MyApp.Web.Endpoint

      hound_session()
    end
  end

  setup do
    :ok = Ecto.Adapters.SQL.Sandbox.checkout(MyApp.Repo)
    metadata = Phoenix.Ecto.SQL.Sandbox.metadata_for(MyApp.Repo, self())
    Hound.start_session(metadata: metadata)
    # Added :ok since `start_session/2` returns a string.
    :ok
  end
end

Tests in the same module do not run concurrently. Only tests in separate modules/files. I.e. the granularity of concurrency is per module and not per test. That’s because tests in the same module/file are usually exercising the same area of the codebase and would not benefit of concurrency.