test: add coverage for Item Tax Template

erpnext/accounts/doctype/item_tax_template/test_item_tax_template.py

@@ -1,8 +1,65 @@
-# Copyright (c) 2018, Frappe Technologies Pvt. Ltd. and Contributors
+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
 # See license.txt
 
+import unittest
+
+import frappe
+
 from erpnext.tests.utils import ERPNextTestSuite
 
+COMPANY = "_Test Company"
+TAX_ACCOUNT = "_Test Account VAT - _TC"
+RECEIVABLE_ACCOUNT = "Debtors - _TC"
+
 
 class TestItemTaxTemplate(ERPNextTestSuite):
-	pass
+	"""Item Tax Template validates its tax rows: each account must belong to the
+	company, be a tax-like account type, and appear only once."""
+
+	def setUp(self):
+		frappe.set_user("Administrator")
+
+	def make_template(self, rows, title="_Test ITT"):
+		doc = frappe.new_doc("Item Tax Template")
+		doc.title = f"{title} {frappe.generate_hash(length=6)}"
+		doc.company = COMPANY
+		for account, rate, not_applicable in rows:
+			doc.append(
+				"taxes",
+				{"tax_type": account, "tax_rate": rate, "not_applicable": not_applicable},
+			)
+		return doc
+
+	def test_valid_template_saves_and_is_named_with_abbr(self):
+		doc = self.make_template([(TAX_ACCOUNT, 9, 0)])
+		doc.insert()
+		self.assertTrue(doc.name.endswith(" - _TC"))
+		self.assertTrue(doc.name.startswith(doc.title))
+
+	def test_duplicate_tax_type_throws(self):
+		doc = self.make_template([(TAX_ACCOUNT, 9, 0), (TAX_ACCOUNT, 5, 0)])
+		self.assertRaises(frappe.ValidationError, doc.insert)
+
+	def test_account_of_wrong_company_throws(self):
+		other_account = frappe.get_all(
+			"Account", {"company": "_Test Company 1", "is_group": 0}, pluck="name"
+		)[0]
+		doc = self.make_template([(other_account, 9, 0)])
+		self.assertRaises(frappe.ValidationError, doc.insert)
+
+	def test_disallowed_account_type_throws(self):
+		# a Receivable account is not Tax/Chargeable/Income/Expense
+		doc = self.make_template([(RECEIVABLE_ACCOUNT, 9, 0)])
+		self.assertRaises(frappe.ValidationError, doc.insert)
+
+	def test_not_applicable_row_has_rate_zeroed(self):
+		doc = self.make_template([(TAX_ACCOUNT, 18, 1)])
+		doc.insert()
+		self.assertEqual(doc.taxes[0].tax_rate, 0)
+
+	@unittest.expectedFailure
+	def test_negative_tax_rate_is_rejected(self):
+		# SUSPECTED BUG: validate never bounds tax_rate, so a negative (or >100) rate
+		# saves silently. Asserts the behaviour we'd want; drop the xfail once bounded.
+		doc = self.make_template([(TAX_ACCOUNT, -5, 0)])
+		self.assertRaises(frappe.ValidationError, doc.insert)