refactor: Use IntegrationTestCase in multiple files

Signed-off-by: David <dgx.arnold@gmail.com>

erpnext/tests/test_regional.py

@@ -1,6 +1,7 @@
 import unittest
 
 import frappe
+from frappe.tests import IntegrationTestCase
 
 import erpnext
 
@@ -10,7 +11,7 @@ def test_method():
 	return "original"
 
 
-class TestInit(unittest.TestCase):
+class TestInit(IntegrationTestCase):
 	def test_regional_overrides(self):
 		frappe.flags.country = "Maldives"
 		self.assertEqual(test_method(), "original")