Ensure workorder sequence is applied on new workorders

Test sequence is applied for multiple operations
Rewrite _reset_work_order_sequence in a more pythonic way
Change _order of mrp.workorder to use sequence
Set sequence on existing workorders after module install

mrp_workorder_sequence/tests/test_mrp_workorder_sequence.py

@@ -1,15 +1,19 @@
 # Copyright 2022 ForgeFlow S.L. (https://www.forgeflow.com)
 # License LGPL-3.0 or later (https://www.gnu.org/licenses/lgpl.html).
 
-from odoo import Command
+from odoo import Command, fields
 from odoo.tests import Form
 
 from odoo.addons.mrp.tests.common import TestMrpCommon
 
 
 class TestMrpWorkorderSequence(TestMrpCommon):
-    def test_mrp_workorder_sequence(self):
-        self.env["mrp.bom"].create(
+    def setUp(self):
+        super().setUp()
+        self._create_bom()
+
+    def _create_bom(self):
+        return self.env["mrp.bom"].create(
             {
                 "product_tmpl_id": self.product_7_template.id,
                 "product_uom_id": self.uom_unit.id,
@@ -104,8 +108,95 @@ class TestMrpWorkorderSequence(TestMrpCommon):
                 ],
             }
         )
+
+    def _create_order(self, product):
         mrp_order_form = Form(self.env["mrp.production"])
-        mrp_order_form.product_id = self.product_7_3
+        mrp_order_form.product_id = product
+        return mrp_order_form.save()
+
+    def test_mrp_workorder_sequence_new_production(self):
+        mrp_order = self._create_order(self.product_7_1)
+        self.assertEqual(len(mrp_order.workorder_ids), 2)
+        for seq, workorder in enumerate(mrp_order.workorder_ids, 1):
+            self.assertEqual(workorder.sequence, seq)
+
+    def test_mrp_workorder_sequence_new_production_new_workorder(self):
+        mrp_order = self._create_order(self.product_7_1)
+        self.assertEqual(len(mrp_order.workorder_ids), 2)
+        max_sequence = max(mrp_order.workorder_ids.mapped("sequence"))
+        mrp_order_form = Form(mrp_order)
+        with mrp_order_form.workorder_ids.new() as wo_form:
+            wo_form.name = "Extra operation"
+            wo_form.workcenter_id = self.workcenter_1
         mrp_order = mrp_order_form.save()
-        for workorder in mrp_order.workorder_ids:
-            self.assertEqual(workorder.sequence, workorder.operation_id.sequence)
+        self.assertEqual(len(mrp_order.workorder_ids), 3)
+        last_wo = fields.first(mrp_order.workorder_ids.sorted(reverse=True))
+        self.assertEqual(last_wo.sequence, max_sequence + 1)
+
+    def test_mrp_workorder_create_multi(self):
+        """
+        Test automatic sequence assignation through create override
+
+        * WO 1: - each added operations without sequence defined
+                get the next sequence after existing WOs
+        * WO 2: - first added operation without sequence
+                get the next sequence after existing WOs
+                - second added operation with sequence defined stays unchanged
+        * WO 3: - first added operation with sequence defined stays unchanged
+                - second added operation without sequence defined
+                get the next sequence from previous operation created
+        """
+        first_mrp_order = self._create_order(self.product_7_1)
+        second_mrp_order = self._create_order(self.product_7_1)
+        third_mrp_order = self._create_order(self.product_7_1)
+        create_values = [
+            {
+                "name": "Extra WO 1.1",
+                "production_id": first_mrp_order.id,
+                "workcenter_id": self.workcenter_1.id,
+                "product_uom_id": self.product_7_1.uom_id.id,
+            },
+            {
+                "name": "Extra WO 1.2",
+                "production_id": first_mrp_order.id,
+                "workcenter_id": self.workcenter_1.id,
+                "product_uom_id": self.product_7_1.uom_id.id,
+            },
+            {
+                "name": "Extra WO 2.1",
+                "production_id": second_mrp_order.id,
+                "workcenter_id": self.workcenter_1.id,
+                "product_uom_id": self.product_7_1.uom_id.id,
+            },
+            {
+                "name": "Extra WO 2.2",
+                "production_id": second_mrp_order.id,
+                "workcenter_id": self.workcenter_1.id,
+                "product_uom_id": self.product_7_1.uom_id.id,
+                "sequence": 6,
+            },
+            {
+                "name": "Extra WO 3.1",
+                "production_id": third_mrp_order.id,
+                "workcenter_id": self.workcenter_1.id,
+                "sequence": 4,
+                "product_uom_id": self.product_7_1.uom_id.id,
+            },
+            {
+                "name": "Extra WO 3.2",
+                "production_id": third_mrp_order.id,
+                "workcenter_id": self.workcenter_1.id,
+                "product_uom_id": self.product_7_1.uom_id.id,
+            },
+        ]
+        created_wos = self.env["mrp.workorder"].create(create_values)
+        expected_res = {
+            "Extra WO 1.1": 3,
+            "Extra WO 1.2": 4,
+            "Extra WO 2.1": 3,
+            "Extra WO 2.2": 6,
+            "Extra WO 3.1": 4,
+            "Extra WO 3.2": 5,
+        }
+        for wo in created_wos:
+            self.assertEqual(wo.sequence, expected_res[wo.name])