Recommanded configuration for LiveViews testing seems useless

[pierrelegall]

The recommended configuration below (found in the README) is for LiveViews testing. However, it seems useless to me: my tests still works (for now) without it. Note I use phoenix_live_view v0.20.3. What's its point?

LiveView

In order to test Phoenix LiveView (as of version 0.17.7) with Wallaby you'll also need to add a function to each mount/3 function in your LiveViews, or use the on_mount live_session lifecycle hook in the router:

defmodule MyApp.Hooks.AllowEctoSandbox do
  import Phoenix.LiveView
  import Phoenix.Component

  def on_mount(:default, _params, _session, socket) do
    allow_ecto_sandbox(socket)
    {:cont, socket}
  end

  defp allow_ecto_sandbox(socket) do
    %{assigns: %{phoenix_ecto_sandbox: metadata}} =
      assign_new(socket, :phoenix_ecto_sandbox, fn ->
        if connected?(socket), do: get_connect_info(socket, :user_agent)
      end)

    Phoenix.Ecto.SQL.Sandbox.allow(metadata, Application.get_env(:your_app, :sandbox))
  end
end

and then including the function usage in the router:

live_session :default, on_mount: MyApp.Hooks.AllowEctoSandbox do
  # ...
end

[mhanberg]

Are you running your tests async: true and with ecto?

You need this in order for your live view process to connect to the same db connection as your test, which is what allows transactional tests.

[pierrelegall]

Ohw I see! It is because my Wallaby tests were configured with async: false 😉

What do you think of a change like this in the README?:

LiveView

In order to run tests on a Phoenix LiveViews (with {:phoenix_live_view, ">= 0.17"}) asynchronously with Wallaby, you'll need to add a hook like this one:

defmodule MyApp.Hooks.AllowEctoSandbox do
  import Phoenix.LiveView
  import Phoenix.Component

  def on_mount(:default, _params, _session, socket) do
    allow_ecto_sandbox(socket)

    {:cont, socket}
  end

  defp allow_ecto_sandbox(socket) do
    %{assigns: %{phoenix_ecto_sandbox: metadata}} =
      assign_new(socket, :phoenix_ecto_sandbox, fn ->
        if connected?(socket), do: get_connect_info(socket, :user_agent)
      end)

    Phoenix.Ecto.SQL.Sandbox.allow(metadata, Application.get_env(:your_app, :sandbox))
  end
end

on your LiveView live_session on_mount:

live_session :default, on_mount: MyApp.Hooks.AllowEctoSandbox do
  # ...
end

or on the on_mount on the LiveView:

on_mount MyApp.Hooks.AllowEctoSandbox

[mhanberg]

it's already under the section describing concurrent testing with Phoenix. I'm not sure it really would make much of a difference.

But, The README is a little long in general, so I think converting it into better organized Guides in hexdocs would be a more helpful change.

[pierrelegall]

The previous "Assets" section does not seems to have something to do with concurrent testing, so it's hard to keep the thread 😅

[pierrelegall]

The README is a little long in general, so I think converting it into better organized Guides in hexdocs would be a more helpful change.

👍