fix(billing): skip zero-amount invoices (no lines) — drop empty move, don't post nothing

fusion_centralize_billing/tests/test_invoice_ledger.py

@@ -120,6 +120,15 @@ class TestLedgerIngest(TransactionCase):
         self.assertAlmostEqual(mv.amount_untaxed, 200.0, places=2)  # captured via reconciling line
         self.assertTrue(any('base/unitemized' in (l.name or '') for l in mv.invoice_line_ids))
 
+    def test_zero_amount_invoice_skipped(self):
+        data = [{'id': 'inv-zero', 'stripe_invoice_id': 'in_z', 'invoice_number': 'NEX-ZERO',
+                 'user_external_id': 'u-1', 'partner_name': 'Acme', 'partner_email': 'ar@acme.test',
+                 'invoice_date': '2026-05-01', 'currency': 'CAD', 'status': 'paid',
+                 'subtotal': 0.0, 'tax': 0.0, 'amount_paid': 0.0, 'paid_at': None, 'items': []}]
+        summary = self.W._ingest_invoices(data, post=False)
+        self.assertFalse(self.Move.search([('x_fc_nexacloud_invoice_id', '=', 'inv-zero')]))
+        self.assertTrue(any(s.get('reason') == 'zero-amount invoice' for s in summary['skipped']))
+
     def test_post_and_reconcile_paid_only(self):
         base = _inv_fixture()[0]
         paid = dict(base, id='inv-paid', invoice_number='NEX-PAID',