feat(billing): idempotent usage ingestion

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fusion_centralize_billing/tests/test_usage.py

@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+from odoo.tests.common import TransactionCase, tagged
+
+
+@tagged('post_install', '-at_install')
+class TestUsageIngestion(TransactionCase):
+
+    def setUp(self):
+        super().setUp()
+        self.metric = self.env['fusion.billing.metric'].sudo().create(
+            {'name': 'CPU seconds', 'code': 'cpu_seconds', 'aggregation': 'sum'})
+        self.plan = self.env['sale.subscription.plan'].sudo().create(
+            {'name': 'Monthly', 'billing_period_value': 1, 'billing_period_unit': 'month'})
+        self.partner = self.env['res.partner'].sudo().create({'name': 'Acme'})
+        self.sub = self.env['sale.order'].sudo().create({
+            'partner_id': self.partner.id, 'is_subscription': True, 'plan_id': self.plan.id,
+        })
+        self.Usage = self.env['fusion.billing.usage'].sudo()
+
+    def test_record_usage_creates_row(self):
+        u = self.Usage._record_usage(
+            self.sub, 'cpu_seconds', 120.0,
+            '2026-05-01 00:00:00', '2026-06-01 00:00:00', idem='nexacloud:cpu:sub1:2026-05-01')
+        self.assertEqual(u.quantity, 120.0)
+        self.assertEqual(u.metric_id, self.metric)
+
+    def test_idempotent_key_updates_not_duplicates(self):
+        k = 'nexacloud:cpu:sub1:2026-05-01'
+        self.Usage._record_usage(self.sub, 'cpu_seconds', 100.0, '2026-05-01', '2026-06-01', idem=k)
+        self.Usage._record_usage(self.sub, 'cpu_seconds', 175.0, '2026-05-01', '2026-06-01', idem=k)
+        rows = self.Usage.search([('idempotency_key', '=', k)])
+        self.assertEqual(len(rows), 1)        # no duplicate
+        self.assertEqual(rows.quantity, 175.0)  # last value wins for the same key