Address code review feedback: Windows-only patch, proper restoration, improved tests

Co-Authored-By: Joe Moura <joao@crewai.com>

tests/litellm_tests/test_encoding.py

@@ -4,14 +4,21 @@ import sys
 import unittest
 from unittest.mock import mock_open, patch
 
-import pytest
-
 from crewai.llm import LLM
+from crewai.patches.litellm_patch import apply_patches, remove_patches
 
 
 class TestLitellmEncoding(unittest.TestCase):
     """Test that the litellm encoding patch works correctly."""
 
+    def setUp(self):
+        """Set up the test environment by applying the patch."""
+        apply_patches()
+
+    def tearDown(self):
+        """Clean up the test environment by removing the patch."""
+        remove_patches()
+
     def test_json_load_with_utf8_encoding(self):
         """Test that json.load is called with UTF-8 encoding."""
         
@@ -25,3 +32,20 @@ class TestLitellmEncoding(unittest.TestCase):
             with open('test.json', 'r') as f:
                 data = json.load(f)
                 self.assertEqual(data['test'], '日本語テキスト')
+    
+    def test_without_patch(self):
+        """Test that demonstrates the issue without the patch."""
+        remove_patches()
+        
+        mock_content = '{"test": "日本語テキスト"}'  # Japanese text that would fail with cp1252
+        
+        with patch('sys.platform', 'win32'):
+            mock_open_without_encoding = mock_open(read_data=mock_content)
+            mock_open_without_encoding.side_effect = UnicodeDecodeError('cp1252', b'\x81', 0, 1, 'invalid start byte')
+            
+            with patch('builtins.open', mock_open_without_encoding):
+                with self.assertRaises(UnicodeDecodeError):
+                    with open('test.json', 'r') as f:
+                        json.load(f)
+        
+        apply_patches()