Phoenix.LiveViewTest doesn't seem to work without sessions

[egze]

Environment

• Elixir version (elixir -v): Elixir 1.10.2 (compiled with Erlang/OTP 22)
• Phoenix version (mix deps): 1.5.1
• Phoenix LiveView version (mix deps): 0.12.1
• NodeJS version (node -v): v13.12.0
• NPM version (npm -v): 6.14.4
• Operating system: macOS 10.15.4

Actual behavior

I am trying to run my website without cookies (for GDPR reasons).

• I removed :fetch_session, :fetch_live_flash, :protect_from_forgery plugs from router.
• Removed websocket: [connect_info: [session: @session_options]] from Phoenix.LiveView.Socket config.
• Removed plug Plug.Session.
• Removed _csrf_token config from app.js.

The application is working fine and no cookies are created, also all live view functionality is working (phx-click).

What is not working:

When I run mix test, I get:

  1) test shows privacy policy (AppWeb.PageLiveTest)
     test/app_web/live/page_live_test.exs:23
     ** (ArgumentError) session not fetched, call fetch_session/2
     code: {:ok, live_view, _disconnected_html} = live(conn, "/")
     stacktrace:
       (plug 1.10.0) lib/plug/conn.ex:1557: Plug.Conn.get_session/1
       (phoenix_live_view 0.12.1) lib/phoenix_live_view/test/live_view_test.ex:343: Phoenix.LiveViewTest.do_connect/7
       test/app_web/live/page_live_test.exs:24: (test)

Expected behavior

I expect that tests still work if the application if configured as sessionless/cookieless. Or that live function has a parameter to not try to load the session.

[josevalim]

Good call! Please let us know if you want to submit a PR, otherwise I will give it a shot later.

[egze]

I absolutely want to give it a shot. Will write later what I’m planning to change when I look in detail how it works.