feat(configurator): per-line lot pricing (derive unit price, keep qty)

fusion_plating/fusion_plating_configurator/tests/test_charge_tax_lot.py

@@ -44,3 +44,13 @@ class TestChargeTaxLot(TransactionCase):
         self.assertEqual(wiz.total_subtotal, 50.0)
         self.assertAlmostEqual(wiz.total_tax, 19.5, places=2)
         self.assertAlmostEqual(wiz.total_amount, 169.5, places=2)
+
+    # ----- Task 4: lot pricing -----
+    def test_lot_onchange_derives_unit_price(self):
+        wiz = self._make_wizard()
+        line = self.env['fp.direct.order.line'].new({
+            'wizard_id': wiz.id, 'quantity': 500, 'lot_total': 1000.0,
+            'is_lot_priced': True,
+        })
+        line._onchange_lot_pricing()
+        self.assertEqual(line.unit_price, 2.0)

fusion_plating/fusion_plating_configurator/wizard/fp_direct_order_line.py

@@ -238,6 +238,21 @@ class FpDirectOrderLine(models.Model):
         string='Unit Price',
         currency_field='currency_id',
     )
+    is_lot_priced = fields.Boolean(
+        string='Lot Price',
+        help='Price the whole quantity as a flat lot total instead of '
+             'per unit. Unit price is derived = lot total / quantity; '
+             'the quantity is preserved for production.',
+    )
+    lot_total = fields.Monetary(
+        string='Lot Total', currency_field='currency_id',
+    )
+
+    @api.onchange('is_lot_priced', 'lot_total', 'quantity')
+    def _onchange_lot_pricing(self):
+        for line in self:
+            if line.is_lot_priced and line.quantity:
+                line.unit_price = (line.lot_total or 0.0) / line.quantity
     line_subtotal = fields.Monetary(
         string='Subtotal',
         currency_field='currency_id',