[IMP] l10n_in: add test case and improve dependency on gst treatment

Now l10n_in_gst_treatment compute field will be depending
on invoice `state`, which will be helpful when any invoice
gets reset to draft

Adding testcases for partner fields on invoice which
tests the same with different usecase

Part-of: odoo/odoo#153773

addons/l10n_in/models/account_invoice.py

@@ -35,7 +35,7 @@ class AccountMove(models.Model):
     l10n_in_reseller_partner_id = fields.Many2one('res.partner', 'Reseller', domain=[('vat', '!=', False)], help="Only Registered Reseller")
     l10n_in_journal_type = fields.Selection(string="Journal Type", related='journal_id.type')
 
-    @api.depends('partner_id', 'partner_id.l10n_in_gst_treatment')
+    @api.depends('partner_id', 'partner_id.l10n_in_gst_treatment', 'state')
     def _compute_l10n_in_gst_treatment(self):
         indian_invoice = self.filtered(lambda m: m.country_code == 'IN')
         for record in indian_invoice:

addons/l10n_in/tests/__init__.py

@@ -1 +1,2 @@
 from . import test_invoice_hsn_summary
+from . import test_partner_details_on_invoice

addons/l10n_in/tests/test_partner_details_on_invoice.py

@@ -0,0 +1,141 @@
+from odoo.addons.account_reports.tests.common import TestAccountReportsCommon
+from odoo.tests import tagged
+import logging
+
+_logger = logging.getLogger(__name__)
+
+@tagged('post_install_l10n', 'post_install', '-at_install')
+class TestReports(TestAccountReportsCommon):
+
+    @classmethod
+    def setUpClass(cls, chart_template_ref="in"):
+        super().setUpClass(chart_template_ref=chart_template_ref)
+        country_in_id = cls.env.ref("base.in").id
+        cls.company_data["company"].write({
+            "vat": "24AAGCC7144L6ZE",
+            "state_id": cls.env.ref("base.state_in_gj").id,
+            "street": "street1",
+            "city": "city1",
+            "zip": "123456",
+            "country_id": country_in_id,
+        })
+        cls.env.company = cls.company_data["company"]
+        cls.partner_a.write({
+            'vat': '27DJMPM8965E1ZE',
+            'l10n_in_gst_treatment':'regular',
+            'state_id': cls.env.ref("base.state_in_mh"),
+            'country_id':country_in_id,
+        })
+        cls.partner_b.write({
+            'vat': '24ABCPM8965E1ZE',
+            'l10n_in_gst_treatment':'composition',
+            'state_id': cls.env.ref("base.state_in_hp"),
+            'country_id':country_in_id,
+        })
+        cls.partner_c = cls.env['res.partner'].create({
+            'name': "Overseas partner",
+            'l10n_in_gst_treatment':'overseas',
+            'state_id': cls.env.ref("base.state_us_1").id,
+            'country_id': cls.env.ref("base.us").id,
+            'zip': "123456",
+        })
+        cls.igst_sale_18 = cls.env['account.chart.template'].ref('igst_sale_18')
+
+    def test_partner_details_change_with_invoice(self):
+        invoice_1 = self.init_invoice(
+            move_type='out_invoice',
+            partner=self.partner_a,
+            amounts=[125, 300, 404],
+            taxes=[self.igst_sale_18]
+        )
+        invoice_2 = self.init_invoice(
+            move_type='out_invoice',
+            partner=self.partner_a,
+            amounts=[250, 600],
+            taxes=[self.igst_sale_18],
+            post=True
+        )
+        # Place of Supply (pos) is same as of state of partner (for journal type sale)
+        expected_pos_id = self.env.ref("base.state_in_mh").id
+        self.assertRecordValues(
+            invoice_1,
+            [{
+                'state': 'draft',
+                'l10n_in_gst_treatment': self.partner_a.l10n_in_gst_treatment,
+                'l10n_in_state_id': expected_pos_id,
+            }]
+        )
+        self.assertRecordValues(
+            invoice_2,
+            [{
+                'state': 'posted',
+                'l10n_in_gst_treatment': self.partner_a.l10n_in_gst_treatment,
+                'l10n_in_state_id': expected_pos_id,
+            }]
+        )
+        self.partner_a.write({
+            'vat': False,
+            'l10n_in_gst_treatment': 'unregistered',
+            'state_id': self.env.ref("base.state_in_tn"), # change state of partner
+        })
+        self.assertRecordValues(
+            invoice_1,
+            [{
+                'state': 'draft',
+                'l10n_in_gst_treatment': self.partner_a.l10n_in_gst_treatment,
+                'l10n_in_state_id': expected_pos_id, # POS doesn't change unless the partner changes
+            }]
+        )
+        self.assertRecordValues(
+            invoice_2,
+            [{ # check gst treatment and pos doesn't change on posted invoice
+                'state': 'posted',
+                'l10n_in_gst_treatment': 'regular',
+            }]
+        )
+        invoice_2.button_draft()
+        self.assertRecordValues(invoice_2, [{
+            'state': 'draft',
+            'l10n_in_gst_treatment': self.partner_a.l10n_in_gst_treatment,
+            'l10n_in_state_id': expected_pos_id,
+        }])
+
+    def test_partner_change_with_invoice(self):
+        out_invoice = self.init_invoice(
+            move_type='out_invoice',
+            partner=self.partner_b,
+            amounts=[40, 160, 25],
+            taxes=[self.igst_sale_18]
+        )
+        in_invoice = self.init_invoice(
+            move_type='in_invoice',
+            partner=self.partner_a,
+            amounts=[452, 58, 110],
+            taxes=[self.igst_sale_18],
+        )
+
+        self.assertRecordValues(
+            out_invoice,
+            [{
+                'state': 'draft',
+                'l10n_in_gst_treatment': self.partner_b.l10n_in_gst_treatment,
+                'l10n_in_state_id': self.env.ref("base.state_in_hp").id,
+            }]
+        )
+        out_invoice.partner_id = self.partner_c
+        self.assertRecordValues(
+            out_invoice,
+            [{
+                'state': 'draft',
+                'l10n_in_gst_treatment': self.partner_c.l10n_in_gst_treatment,
+                'l10n_in_state_id': self.env.ref("l10n_in.state_in_oc").id,
+            }]
+        )
+        self.assertRecordValues(
+            in_invoice,
+            [{
+                'state': 'draft',
+                'l10n_in_gst_treatment': self.partner_a.l10n_in_gst_treatment,
+                'l10n_in_state_id': self.env.company.state_id.id,
+            }]
+        )