diff --git a/erpnext/accounts/doctype/chart_of_accounts_importer/test_chart_of_accounts_importer.py b/erpnext/accounts/doctype/chart_of_accounts_importer/test_chart_of_accounts_importer.py
index f1248393aca..524e59ab07c 100644
--- a/erpnext/accounts/doctype/chart_of_accounts_importer/test_chart_of_accounts_importer.py
+++ b/erpnext/accounts/doctype/chart_of_accounts_importer/test_chart_of_accounts_importer.py
@@ -1,8 +1,54 @@
-# Copyright (c) 2019, Frappe Technologies Pvt. Ltd. and Contributors
+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
 # See license.txt
 
+import frappe
+
+from erpnext.accounts.doctype.chart_of_accounts_importer.chart_of_accounts_importer import (
+	build_forest,
+	validate_columns,
+	validate_missing_roots,
+)
 from erpnext.tests.utils import ERPNextTestSuite
 
+# columns: account_name, parent_account, account_number, parent_account_number,
+#          is_group, account_type, root_type, account_currency
+ROOT = ["Assets", "Assets", "", "", 1, "", "Asset", "INR"]
+CHILD = ["Cash", "Assets", "", "", 0, "Cash", "Asset", "INR"]
+
 
 class TestChartofAccountsImporter(ERPNextTestSuite):
-	pass
+	"""The importer parses an uploaded CoA into a nested tree and validates its
+	shape. These cover the parsing/validation helpers without a file upload."""
+
+	def test_validate_columns_rejects_blank_file(self):
+		self.assertRaises(frappe.ValidationError, validate_columns, [])
+
+	def test_validate_columns_requires_eight_columns(self):
+		self.assertRaises(frappe.ValidationError, validate_columns, [["a", "b", "c"]])
+		# the standard template width passes
+		validate_columns([ROOT])
+
+	def test_build_forest_nests_child_under_parent(self):
+		forest = build_forest([ROOT, CHILD])
+		self.assertIn("Assets", forest)
+		self.assertIn("Cash", forest["Assets"])
+
+	def test_build_forest_rejects_unknown_parent(self):
+		orphan = ["Cash", "Missing Parent", "", "", 0, "Cash", "Asset", "INR"]
+		self.assertRaises(frappe.ValidationError, build_forest, [orphan])
+
+	def test_build_forest_requires_account_name(self):
+		nameless = ["", "Assets", "", "", 0, "Cash", "Asset", "INR"]
+		self.assertRaises(frappe.ValidationError, build_forest, [ROOT, nameless])
+
+	def test_validate_missing_roots_requires_all_root_types(self):
+		present = ("Asset", "Liability", "Expense", "Income")  # Equity missing
+		self.assertRaises(
+			frappe.ValidationError,
+			validate_missing_roots,
+			[{"root_type": rt} for rt in present],
+		)
+		# all five root types present -> no error
+		validate_missing_roots(
+			[{"root_type": rt} for rt in ("Asset", "Liability", "Expense", "Income", "Equity")]
+		)