[FIX] l10n_it_reverse_charge: Negative lines management

Otherwise bills having negative lines raise an error when confirmed

l10n_it_reverse_charge/models/account_move.py

@@ -142,8 +142,11 @@ def _rc_get_move_line_to_reconcile(self):
         else:
             raise UserError(_("Only inbound and outbound moves are supported"))
 
+        to_reconcile_move_lines = self.line_ids.filtered(
+            lambda ml: ml.account_id.reconcile
+        )
         is_zero = self.currency_id.is_zero
-        for move_line in self.line_ids:
+        for move_line in to_reconcile_move_lines:
             field_value = getattr(move_line, line_field)
             if not is_zero(field_value) and move_line.account_id.account_type in (
                 "asset_receivable",

l10n_it_reverse_charge/tests/test_rc.py

@@ -271,3 +271,16 @@ def test_description_lines(self):
 
         # Assert
         self.assertEqual(bill.state, "posted")
+
+    def test_negative_lines(self):
+        """A Reverse Charge Bill can be confirmed
+        when contains negative lines."""
+        # Arrange: Create a Reverse Charge Bill with negative lines
+        bill = self.create_invoice(
+            self.supplier_extraEU,
+            amounts=[100, -10],
+            taxes=self.tax_0_pur,
+        )
+
+        # Assert
+        self.assertEqual(bill.state, "posted")