restructure test_main.py structure to allow setup and teardown of testing suite

Author: harryswift01

tests/test_CodeEntropy/test_main.py

@@ -1,3 +1,6 @@
+import os
+import shutil
+import tempfile
 import unittest
 from unittest.mock import MagicMock, patch
 
@@ -9,6 +12,22 @@ class TestMain(unittest.TestCase):
     Unit tests for the main functionality of CodeEntropy.
     """
 
+    def setUp(self):
+        """
+        Set up a temporary directory as the working directory before each test.
+        """
+        self.test_dir = tempfile.mkdtemp(prefix="CodeEntropy_")
+        self._orig_dir = os.getcwd()
+        os.chdir(self.test_dir)
+
+    def tearDown(self):
+        """
+        Clean up by removing the temporary directory and restoring the original working
+        directory.
+        """
+        os.chdir(self._orig_dir)
+        shutil.rmtree(self.test_dir)
+
     @patch("CodeEntropy.main.sys.exit")
     @patch("CodeEntropy.main.RunManager")
     def test_main_successful_run(self, mock_RunManager, mock_exit):