Documented here: https://github.com/phoenixframework/phoenix_ecto#concurrent-browser-tests

@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.

I see — to clarify, the tests are indeed split in two separate files, and each file has its own module, e.g.:

defmodule LoginTest do
  use MyApp.Web.IntegrationCase, async: true
  # ...
end

However, they do exercise the same main web application, just doing different things (one tests logging in, the other tests creating data). Would that mean that I cannot run them concurrently?

Hi @svilen,

Wondering if you were able to get Hound to work with an async test suite using ChromeDriver? I’ve struggled for days trying to get this to work before punting and running everything synchronously and was reminded about it this morning: Async Hound tests failing sporadically with ChromeDriver

Thanks!