test: add test case for item master maintain-stock
diff --git a/erpnext/stock/doctype/item/test_item.py b/erpnext/stock/doctype/item/test_item.py
index 89da721..1cee553 100644
--- a/erpnext/stock/doctype/item/test_item.py
+++ b/erpnext/stock/doctype/item/test_item.py
@@ -786,6 +786,36 @@
 		item.save()
 		self.assertTrue(len(item.customer_code) > 140)
 
+	def test_update_is_stock_item(self):
+		# Step - 1: Create an Item with Maintain Stock enabled
+		item = make_item(properties={"is_stock_item": 1})
+
+		# Step - 2: Disable Maintain Stock
+		item.is_stock_item = 0
+		item.save()
+		item.reload()
+		self.assertEqual(item.is_stock_item, 0)
+
+		# Step - 3: Create Product Bundle
+		pb = frappe.new_doc("Product Bundle")
+		pb.new_item_code = item.name
+		pb.flags.ignore_mandatory = True
+		pb.save()
+
+		# Step - 4: Try to enable Maintain Stock, should throw a validation error
+		item.is_stock_item = 1
+		self.assertRaises(frappe.ValidationError, item.save)
+		item.reload()
+
+		# Step - 5: Delete Product Bundle
+		pb.delete()
+
+		# Step - 6: Again try to enable Maintain Stock
+		item.is_stock_item = 1
+		item.save()
+		item.reload()
+		self.assertEqual(item.is_stock_item, 1)
+
 
 def set_item_variant_settings(fields):
 	doc = frappe.get_doc("Item Variant Settings")