diff --git a/test/decentralised_book_index/sync/sync/author_sync_test.exs b/test/decentralised_book_index/sync/sync/author_sync_test.exs
index a611348..7087a18 100644
--- a/test/decentralised_book_index/sync/sync/author_sync_test.exs
+++ b/test/decentralised_book_index/sync/sync/author_sync_test.exs
@@ -26,17 +26,13 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.AuthorSyncTest do
         updated_at: "2025-03-21T09:20:48.791539Z"
       }
 
-      {:ok, inserted_at, 0} = DateTime.from_iso8601(author[:inserted_at])
-      {:ok, updated_at, 0} = DateTime.from_iso8601(author[:updated_at])
-
       assert :ok = AuthorSync.create_update(author, server.id)
       assert {:ok, saved_author} = Metadata.get_author_by_id(author.id)
 
       author =
         author
-        |> Map.replace(:inserted_at, inserted_at)
-        |> Map.replace(:updated_at, updated_at)
         |> Map.delete(:author_alias_registry_id)
+        |> datetime_from_iso8601_for_map()
 
       assert get_submap(saved_author, author) == author
       assert nil != saved_author.author_alias_registry_id
@@ -56,16 +52,12 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.AuthorSyncTest do
         updated_at: "2025-03-21T09:20:48.791539Z"
       }
 
-      {:ok, inserted_at, 0} = DateTime.from_iso8601(author[:inserted_at])
-      {:ok, updated_at, 0} = DateTime.from_iso8601(author[:updated_at])
-
       assert :ok = AuthorSync.create_update(author, server.id)
       assert {:ok, saved_author} = Metadata.get_author_by_id(author.id)
 
       author =
         author
-        |> Map.replace(:inserted_at, inserted_at)
-        |> Map.replace(:updated_at, updated_at)
+        |> datetime_from_iso8601_for_map()
 
       assert get_submap(saved_author, author) == author
       assert nil != saved_author.author_alias_registry_id
@@ -88,7 +80,7 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.AuthorSyncTest do
       assert :ok = AuthorSync.create_update(author_attrs, server.id)
       assert {:ok, saved_author} = Metadata.get_author_by_id(author.id)
 
-      assert author = saved_author
+      assert get_submap(author, author_attrs) == get_submap(saved_author, author_attrs)
     end
 
     test "the local existing author wouldn't updated", %{user: user} do
diff --git a/test/decentralised_book_index/sync/sync/book_sync_test.exs b/test/decentralised_book_index/sync/sync/book_sync_test.exs
index d45d951..3aaa17b 100644
--- a/test/decentralised_book_index/sync/sync/book_sync_test.exs
+++ b/test/decentralised_book_index/sync/sync/book_sync_test.exs
@@ -32,20 +32,17 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.BookSyncTest do
         updated_at: "2025-04-01T18:14:25.754055Z"
       }
 
-      {:ok, inserted_at, 0} = DateTime.from_iso8601(book[:inserted_at])
-      {:ok, updated_at, 0} = DateTime.from_iso8601(book[:updated_at])
-
       assert :ok = BookSync.create_update(book, server.id)
       assert {:ok, saved_book} = Metadata.get_book_by_id(book.id)
 
       book =
         book
-        |> Map.replace(:inserted_at, inserted_at)
-        |> Map.replace(:updated_at, updated_at)
+	|> datetime_from_iso8601_for_map()
         |> Map.replace(:published, Date.from_iso8601!(book[:published]))
 
       assert nil != saved_book.book_editions_registry_id
       assert server.id == saved_book.dbi_server_id
+      assert get_submap(saved_book, book) == book
     end
 
     test "a new book has the same editions registry" do
@@ -68,20 +65,17 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.BookSyncTest do
         book_editions_registry_id: "1ed81d9e-3757-472a-aa3b-44fcdfbe770a"
       }
 
-      {:ok, inserted_at, 0} = DateTime.from_iso8601(book[:inserted_at])
-      {:ok, updated_at, 0} = DateTime.from_iso8601(book[:updated_at])
-
       assert :ok = BookSync.create_update(book, server.id)
       assert {:ok, saved_book} = Metadata.get_book_by_id(book.id)
 
       book =
         book
-        |> Map.replace(:inserted_at, inserted_at)
-        |> Map.replace(:updated_at, updated_at)
+	|> datetime_from_iso8601_for_map()
         |> Map.replace(:published, Date.from_iso8601!(book[:published]))
 
       assert nil != saved_book.book_editions_registry_id
       assert server.id == saved_book.dbi_server_id
+      assert get_submap(saved_book, book) == book
     end
 
     test "a new book with relationships will be created" do
@@ -166,10 +160,10 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.BookSyncTest do
       }
 
       assert :ok = BookSync.create_update(book_attrs, server.id)
-      assert {:ok, saved_book} = Metadata.get_book_by_id(book.id)
+      assert {:ok, _saved_book} = Metadata.get_book_by_id(book.id)
     end
 
-    test "the local existing book wouldn't updated", %{user: user} do
+    test "the local existing book wouldn't updated" do
       server = generate(dbi_server(url: @test_server_endpoint))
 
       book = generate(book())
diff --git a/test/decentralised_book_index/sync/sync/dbi_server_sync_test.exs b/test/decentralised_book_index/sync/sync/dbi_server_sync_test.exs
index 9ffe237..93a93f4 100644
--- a/test/decentralised_book_index/sync/sync/dbi_server_sync_test.exs
+++ b/test/decentralised_book_index/sync/sync/dbi_server_sync_test.exs
@@ -17,11 +17,11 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.DBIServerSyncTest do
       server = generate(dbi_server(url: @test_server_endpoint))
 
       dbi_server = %{
-               id: "0c0647ec-07ef-4caa-b683-5847dbfbe5cc",
-               name: "Test",
-               url: "http://localhost:4001",
-               inserted_at: "2025-03-22T20:07:30.766249Z",
-               updated_at: "2025-05-04T18:48:44.213309Z"
+        id: "0c0647ec-07ef-4caa-b683-5847dbfbe5cc",
+        name: "Test",
+        url: "http://localhost:4001",
+        inserted_at: "2025-03-22T20:07:30.766249Z",
+        updated_at: "2025-05-04T18:48:44.213309Z"
       }
 
       {:ok, inserted_at, 0} = DateTime.from_iso8601(dbi_server[:inserted_at])
@@ -35,27 +35,30 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.DBIServerSyncTest do
         |> Map.replace(:inserted_at, inserted_at)
         |> Map.replace(:updated_at, updated_at)
 
-      assert dbi_server = saved_dbi_server
+      assert dbi_server == get_submap(saved_dbi_server, dbi_server)
       assert server.id == saved_dbi_server.dbi_server_id
     end
 
     test "update an existing dbi_server", %{user: user} do
       server = generate(dbi_server(url: @test_server_endpoint))
 
-      {:ok, dbi_server} = Metadata.create_dbi_server("Test", "http://localhost:4001", false, actor: user)
+      {:ok, dbi_server} =
+        Metadata.create_dbi_server("Test", "http://localhost:4001", false, actor: user)
 
       dbi_server_attrs = %{
-               id: dbi_server.id,
-               name: "Test",
-               url: "http://localhost:4001",
-               inserted_at: "2025-03-22T20:07:30.766249Z",
-               updated_at: "2025-05-04T18:48:44.213309Z"
+        id: dbi_server.id,
+        name: "Test",
+        url: "http://localhost:4001",
+        inserted_at: "2025-03-22T20:07:30.766249Z",
+        updated_at: "2025-05-04T18:48:44.213309Z"
       }
 
       assert :ok = DBIServerSync.create_update(dbi_server_attrs, server.id)
       assert {:ok, saved_dbi_server} = Metadata.get_dbi_server_by_id(dbi_server.id)
 
-      assert dbi_server_attrs = saved_dbi_server
+      assert datetime_from_iso8601_for_map(dbi_server_attrs) ==
+               get_submap(saved_dbi_server, dbi_server_attrs)
+
       assert server.id == saved_dbi_server.dbi_server_id
     end
   end
diff --git a/test/decentralised_book_index/sync/sync/publisher_sync_test.exs b/test/decentralised_book_index/sync/sync/publisher_sync_test.exs
index 2a83919..c8a4387 100644
--- a/test/decentralised_book_index/sync/sync/publisher_sync_test.exs
+++ b/test/decentralised_book_index/sync/sync/publisher_sync_test.exs
@@ -23,9 +23,6 @@ defmodule DecentralisedBookIndex.Sync.DataTransformers.PublisherSyncTest do
         updated_at: "2025-03-21T09:20:48.791539Z"
       }
 
-      {:ok, inserted_at, 0} = DateTime.from_iso8601(publisher[:inserted_at])
-      {:ok, updated_at, 0} = DateTime.from_iso8601(publisher[:updated_at])
-
       assert :ok = PublisherSync.create_update(publisher, server.id)
       assert {:ok, saved_publisher} = Metadata.get_publisher_by_id(publisher.id)
 
diff --git a/test/decentralised_book_index/sync/sync_tasks/sync_authors_task_test.exs b/test/decentralised_book_index/sync/sync_tasks/sync_authors_task_test.exs
index f5c9d7e..e30f5be 100644
--- a/test/decentralised_book_index/sync/sync_tasks/sync_authors_task_test.exs
+++ b/test/decentralised_book_index/sync/sync_tasks/sync_authors_task_test.exs
@@ -16,10 +16,10 @@ defmodule DecentralisedBookIndex.SyncTasks.SyncAuthorsTaskTest do
     test "sync authors", %{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.create_author("Author2", "An description", nil, nil, actor: user)
+      {:ok, _author} = Metadata.create_author("Author", "An description", nil, nil, actor: user)
+      {:ok, _author} = Metadata.create_author("Author2", "An description", nil, nil, actor: user)
 
-      assert server = SyncAuthorsTask.sync(server)
+      assert ^server = SyncAuthorsTask.sync(server)
     end
   end
 end
diff --git a/test/decentralised_book_index/sync/sync_tasks/sync_books_task_test.exs b/test/decentralised_book_index/sync/sync_tasks/sync_books_task_test.exs
index 527a7cd..7b9c90f 100644
--- a/test/decentralised_book_index/sync/sync_tasks/sync_books_task_test.exs
+++ b/test/decentralised_book_index/sync/sync_tasks/sync_books_task_test.exs
@@ -2,7 +2,6 @@ defmodule DecentralisedBookIndex.SyncTasks.SyncBookTaskTest do
   use DecentralisedBookIndex.DataCase
 
   alias DecentralisedBookIndex.SyncTasks.SyncBooksTask
-  alias DecentralisedBookIndex.Metadata
 
   alias DecentralisedBookIndex.TestEndpoints
   @test_server_endpoint TestEndpoints.test_api_endpoint()
@@ -14,7 +13,7 @@ defmodule DecentralisedBookIndex.SyncTasks.SyncBookTaskTest do
       _book = generate(book())
       _book = generate(book())
 
-      assert server = SyncBooksTask.sync(server)
+      assert ^server = SyncBooksTask.sync(server)
     end
   end
 end
diff --git a/test/decentralised_book_index/sync/sync_tasks/sync_dbi_server_task_test.exs b/test/decentralised_book_index/sync/sync_tasks/sync_dbi_server_task_test.exs
index 009cc69..6155399 100644
--- a/test/decentralised_book_index/sync/sync_tasks/sync_dbi_server_task_test.exs
+++ b/test/decentralised_book_index/sync/sync_tasks/sync_dbi_server_task_test.exs
@@ -19,7 +19,7 @@ defmodule DecentralisedBookIndex.SyncTasks.SyncDBIServerTaskTest do
       {:ok, _dbi_server} = Metadata.create_dbi_server("Test", "http://localhost:4001", false, actor: user)
       {:ok, _dbi_server} = Metadata.create_dbi_server("Test2", "http://localhost:4001", false, actor: user)
 
-      assert server = SyncDBIServerTask.sync(server)
+      assert ^server = SyncDBIServerTask.sync(server)
     end
   end
 end
diff --git a/test/decentralised_book_index/sync/sync_tasks/sync_publishers_task_test.exs b/test/decentralised_book_index/sync/sync_tasks/sync_publishers_task_test.exs
index 8f91916..cbb0b8e 100644
--- a/test/decentralised_book_index/sync/sync_tasks/sync_publishers_task_test.exs
+++ b/test/decentralised_book_index/sync/sync_tasks/sync_publishers_task_test.exs
@@ -19,7 +19,7 @@ defmodule DecentralisedBookIndex.SyncTasks.SyncPublishersTaskTest do
       {:ok, _publisher} = Metadata.create_publisher("Publisher", actor: user)
       {:ok, _publisher} = Metadata.create_publisher("Publisher2", actor: user)
 
-      assert server = SyncPublishersTask.sync(server)
+      assert ^server = SyncPublishersTask.sync(server)
     end
   end
 end
diff --git a/test/decentralised_book_index/sync/sync_tasks/sync_server_task_test.exs b/test/decentralised_book_index/sync/sync_tasks/sync_server_task_test.exs
index e664c7d..a4ea6c2 100644
--- a/test/decentralised_book_index/sync/sync_tasks/sync_server_task_test.exs
+++ b/test/decentralised_book_index/sync/sync_tasks/sync_server_task_test.exs
@@ -3,9 +3,6 @@ defmodule DecentralisedBookIndex.SyncTasks.SyncServerTaskTest do
 
   alias DecentralisedBookIndex.SyncTasks.SyncServerTask
 
-  alias DecentralisedBookIndex.Sync.ApiClients.FetchJson
-  alias DecentralisedBookIndex.Sync.AuthorSync
-
   alias DecentralisedBookIndex.Metadata
 
   alias DecentralisedBookIndex.TestEndpoints
@@ -18,19 +15,19 @@ defmodule DecentralisedBookIndex.SyncTasks.SyncServerTaskTest do
 
   describe "sync all" do
     test "servers", %{user: user} do
-      server = generate(dbi_server(url: @test_server_endpoint))
-      {:ok, author} = Metadata.create_author("Author", "An description", nil, nil, actor: user)
+      _server = generate(dbi_server(url: @test_server_endpoint))
+      {:ok, _author} = Metadata.create_author("Author", "An description", nil, nil, actor: user)
 
-      assert server = SyncServerTask.sync_all()
+      assert :ok = SyncServerTask.sync_all()
     end
   end
 
   describe "sync one" do
     test "server", %{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.create_author("Author", "An description", nil, nil, actor: user)
 
-      assert server = SyncServerTask.sync_one(server)
+      assert :ok = SyncServerTask.sync_one(server)
     end
   end
 end