fix: adjust TransactionCode code for prenote returns

See: https://moov-io.slack.com/archives/CD9J8EJKX/p1710827043313929

pkg/response/entry_transformer.go

@@ -107,6 +107,11 @@ func (t *ReturnTransformer) MorphEntry(fh ach.FileHeader, ed *ach.EntryDetail, a
 	switch ed.TransactionCode {
 	case ach.CheckingCredit, ach.CheckingDebit, ach.SavingsCredit, ach.SavingsDebit:
 		out.TransactionCode = ed.TransactionCode - 1
+
+	case ach.CheckingPrenoteCredit, ach.CheckingPrenoteDebit, ach.SavingsPrenoteCredit, ach.SavingsPrenoteDebit,
+		ach.GLPrenoteCredit, ach.GLPrenoteDebit, ach.LoanPrenoteCredit:
+		out.TransactionCode = ed.TransactionCode - 2
+
 	default:
 		out.TransactionCode = ed.TransactionCode
 	}

pkg/response/entry_transformer_test.go

@@ -73,3 +73,52 @@ func TestMorphEntry__Return(t *testing.T) {
 	require.Equal(t, "R01", out.Addenda99.ReturnCode)
 	require.Equal(t, "23138010", out.Addenda99.OriginalDFI)
 }
+
+func TestMorphEntry__Prenote(t *testing.T) {
+	file, err := ach.ReadFile(filepath.Join("..", "..", "testdata", "prenote.ach"))
+	require.NoError(t, err)
+
+	t.Run("correction", func(t *testing.T) {
+		action := service.Action{
+			Correction: &service.Correction{
+				Code: "C01",
+				Data: "45111616",
+			},
+		}
+		ed := file.Batches[0].GetEntries()[0]
+		ed.TransactionCode = ach.CheckingPrenoteCredit
+
+		xform := &CorrectionTransformer{}
+		out, err := xform.MorphEntry(file.Header, ed, &action)
+		require.NoError(t, err)
+
+		require.Equal(t, ach.CheckingReturnNOCCredit, out.TransactionCode)
+		require.NotEqual(t, ed.TraceNumber, out.TraceNumber)
+		require.Equal(t, ed.TraceNumber, out.Addenda98.OriginalTrace)
+
+		require.NotNil(t, out.Addenda98)
+		require.Equal(t, "C01", out.Addenda98.ChangeCode)
+		require.Equal(t, "45111616", out.Addenda98.CorrectedData)
+	})
+
+	t.Run("return", func(t *testing.T) {
+		action := service.Action{
+			Return: &service.Return{
+				Code: "R01",
+			},
+		}
+		ed := file.Batches[0].GetEntries()[0]
+		ed.TransactionCode = ach.CheckingPrenoteCredit
+
+		xform := &ReturnTransformer{}
+		out, err := xform.MorphEntry(file.Header, ed, &action)
+		require.NoError(t, err)
+
+		require.Equal(t, ach.CheckingReturnNOCCredit, out.TransactionCode)
+		require.NotEqual(t, ed.TraceNumber, out.TraceNumber)
+
+		require.NotNil(t, out.Addenda99)
+		require.Equal(t, ed.TraceNumber, out.Addenda99.OriginalTrace)
+		require.Equal(t, "R01", out.Addenda99.ReturnCode)
+	})
+}