Update Author to sync only a new non-local data.

test/decentralised_book_index/sync/sync/author_sync_test.exs

@@ -90,5 +90,51 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.AuthorSyncTest do
 
       assert author = saved_author
     end
+
+    test "the local existing author wouldn't updated", %{user: user} do
+      server = generate(dbi_server(url: @test_server_endpoint))
+
+      {:ok, author} = Metadata.create_author("Author", "An description", nil, nil, actor: user)
+
+      author_attrs = %{
+        id: author.id,
+        name: "Author",
+        description: "Something2",
+        avatar_url: "/images/avatar.png",
+        author_alias_registry_id: nil,
+        inserted_at: "2025-03-21T09:20:48.791539Z",
+        updated_at: "2025-03-21T09:20:48.791539Z"
+      }
+
+      assert :ok = AuthorSync.create_update(author_attrs, server.id)
+      assert {:ok, saved_author} = Metadata.get_author_by_id(author.id)
+
+      assert get_submap(saved_author, author_attrs) != author_attrs
+      assert saved_author.name == "Author"
+      assert saved_author.dbi_server_id == nil
+    end
+
+    test "old author wouldn't be sync", %{user: user} do
+      server = generate(dbi_server(url: @test_server_endpoint))
+
+      {:ok, author} = Metadata.create_author("Author", "An description", nil, nil, actor: user)
+      {:ok, author} = Metadata.assign_author_dbi_server(author, server.id, actor: user)
+
+      author_attrs = %{
+        id: author.id,
+        name: "Author",
+        description: "Something2",
+        avatar_url: "/images/avatar.png",
+        author_alias_registry_id: nil,
+        inserted_at: "2025-03-21T09:20:48.791539Z",
+        updated_at: "2025-03-21T09:20:48.791539Z"
+      }
+
+      assert :ok = AuthorSync.create_update(author_attrs, server.id)
+      assert {:ok, saved_author} = Metadata.get_author_by_id(author.id)
+
+      assert get_submap(saved_author, author_attrs) != author_attrs
+      assert saved_author.name == "Author"
+    end
   end
 end