[tools/shoestring] fix: address feedback

tools/shoestring/tests/internal/test_CertificateFactory.py

@@ -1,6 +1,7 @@
 import datetime
 import os
 import re
+import shutil
 import tempfile
 import unittest
 from pathlib import Path
@@ -288,6 +289,10 @@ def _load_binary_file_data(filename):
 					factory.generate_ca_certificate(ca_common_name)
 					factory.package(package_directory)
 
+				# Sanity:
+				shutil.rmtree(certificate_directory)
+				assert not ca_private_key_path.exists()
+
 				# Act:
 				with CertificateFactory(self._create_executor(), ca_private_key_path) as renew_factory:
 					renew_factory.reuse_ca_certificate(ca_common_name, Path(package_directory))