Add large battery of tests, primarily workers

test/music_library/batch_test.exs

@@ -0,0 +1,68 @@
+defmodule MusicLibrary.BatchTest do
+  use MusicLibrary.DataCase
+
+  import MusicLibrary.Fixtures.Records
+
+  alias MusicLibrary.Batch
+  alias MusicLibrary.Records.Record
+
+  describe "run_on_all/3" do
+    test "processes all records and returns empty list on success" do
+      _r1 = record()
+      _r2 = record()
+
+      assert {:ok, []} =
+               Batch.run_on_all(Record, "record", fn _record ->
+                 :ok
+               end)
+    end
+
+    @tag :capture_log
+    test "collects failed record IDs" do
+      r1 = record()
+      r2 = record()
+
+      assert {:ok, failed_ids} =
+               Batch.run_on_all(Record, "record", fn _record ->
+                 {:error, :test_failure}
+               end)
+
+      assert length(failed_ids) == 2
+      assert r1.id in failed_ids
+      assert r2.id in failed_ids
+    end
+
+    @tag :capture_log
+    test "handles mixed success and failure" do
+      r1 = record()
+      _r2 = record()
+
+      assert {:ok, failed_ids} =
+               Batch.run_on_all(Record, "record", fn record ->
+                 if record.id == r1.id do
+                   {:error, :test_failure}
+                 else
+                   :ok
+                 end
+               end)
+
+      assert failed_ids == [r1.id]
+    end
+
+    test "works with empty table" do
+      assert {:ok, []} =
+               Batch.run_on_all(Record, "record", fn _record ->
+                 :ok
+               end)
+    end
+
+    test "accepts {:ok, result} as success" do
+      _r1 = record()
+
+      assert {:ok, []} =
+               Batch.run_on_all(Record, "record", fn _record ->
+                 {:ok, :updated}
+               end)
+    end
+  end
+end