CommonFixes, Transmogrifier: Fix tests.

lib/pleroma/web/activity_pub/object_validators/common_fixes.ex

@@ -20,13 +20,15 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes do
   require Pleroma.Constants
 
   def cast_and_filter_recipients(message, field, follower_collection, field_fallback \\ []) do
-    # calling this here since we need to fix as:Public address before ObjectID cast throws it out
-    message =
-      message
+    # Fix as:Public/Public before ObjectID casting drops it, but keep `field_fallback`
+    # semantics (only used when the field is missing).
+    recipients =
+      %{field => message[field] || field_fallback}
       |> Transmogrifier.fix_addressing_list(field)
       |> Transmogrifier.fix_addressing_public(field)
+      |> Map.fetch!(field)
 
-    {:ok, data} = ObjectValidators.Recipients.cast(message[field] || field_fallback)
+    {:ok, data} = ObjectValidators.Recipients.cast(recipients)
 
     data =
       Enum.reject(data, fn x ->

lib/pleroma/web/activity_pub/transmogrifier.ex

@@ -109,10 +109,12 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   https://codeberg.org/bovine/bovine/issues/53
   """
   def fix_addressing_public(map, field) do
+    addrs = Map.get(map, field, []) |> List.wrap()
+
     Map.put(
       map,
       field,
-      Enum.map(Map.get(map, field), fn
+      Enum.map(addrs, fn
         "Public" -> Pleroma.Constants.as_public()
         "as:Public" -> Pleroma.Constants.as_public()
         x -> x