Introduce group posts

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

test/federation/activity_pub/transmogrifier/leave_test.exs

@@ -0,0 +1,60 @@
+defmodule Mobilizon.Federation.ActivityPub.Transmogrifier.LeaveTest do
+  use Mobilizon.DataCase
+
+  import Mobilizon.Factory
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Events
+  alias Mobilizon.Events.{Event, Participant}
+  alias Mobilizon.Federation.ActivityPub
+  alias Mobilizon.Federation.ActivityPub.Transmogrifier
+
+  describe "handle incoming leave activities on events" do
+    test "it accepts Leave activities" do
+      %Actor{url: _organizer_url} = organizer = insert(:actor)
+      %Actor{url: participant_url} = participant_actor = insert(:actor)
+
+      %Event{url: event_url} =
+        event = insert(:event, organizer_actor: organizer, join_options: :restricted)
+
+      organizer_participation =
+        %Participant{} = insert(:participant, event: event, actor: organizer, role: :creator)
+
+      {:ok, _join_activity, _participation} = ActivityPub.join(event, participant_actor)
+
+      join_data =
+        File.read!("test/fixtures/mobilizon-leave-activity.json")
+        |> Jason.decode!()
+        |> Map.put("actor", participant_url)
+        |> Map.put("object", event_url)
+
+      assert {:ok, activity, _} = Transmogrifier.handle_incoming(join_data)
+
+      assert activity.data["object"] == event_url
+      assert activity.data["actor"] == participant_url
+
+      # The only participant left is the organizer
+      assert event.id
+             |> Events.list_participants_for_event()
+             |> Map.get(:elements)
+             |> Enum.map(& &1.id) ==
+               [organizer_participation.id]
+    end
+
+    test "it refuses Leave activities when actor is the only organizer" do
+      %Actor{url: organizer_url} = organizer = insert(:actor)
+
+      %Event{url: event_url} =
+        event = insert(:event, organizer_actor: organizer, join_options: :restricted)
+
+      %Participant{} = insert(:participant, event: event, actor: organizer, role: :creator)
+
+      join_data =
+        File.read!("test/fixtures/mobilizon-leave-activity.json")
+        |> Jason.decode!()
+        |> Map.put("actor", organizer_url)
+        |> Map.put("object", event_url)
+
+      assert :error = Transmogrifier.handle_incoming(join_data)
+    end
+  end
+end