test: add test confirming embedded array behavior

test/embeddable_resource_test.exs

@@ -1,7 +1,7 @@
 defmodule AshPostgres.EmbeddableResourceTest do
   @moduledoc false
   use AshPostgres.RepoCase, async: false
-  alias AshPostgres.Test.{Api, Post}
+  alias AshPostgres.Test.{Api, Author, Bio, Post}
 
   require Ash.Query
 
@@ -18,4 +18,17 @@ defmodule AshPostgres.EmbeddableResourceTest do
     assert %{calc_returning_json: %AshPostgres.Test.Money{amount: 100, currency: :usd}} =
              Api.load!(post, :calc_returning_json)
   end
+
+  test "embeds with list attributes set to nil are loaded as nil" do
+    post =
+      Author
+      |> Ash.Changeset.new(%{bio: %Bio{list_of_strings: nil}})
+      |> Api.create!()
+
+    assert is_nil(post.bio.list_of_strings)
+
+    post = Api.reload!(post)
+
+    assert is_nil(post.bio.list_of_strings)
+  end
 end

test/support/resources/bio.ex

@@ -10,5 +10,10 @@ defmodule AshPostgres.Test.Bio do
     attribute(:title, :string)
     attribute(:bio, :string)
     attribute(:years_of_experience, :integer)
+
+    attribute :list_of_strings, {:array, :string} do
+      allow_nil?(true)
+      default(nil)
+    end
   end
 end