test: update test to use invalid Unicode that triggers encoding error

tests/basic/test_io.py

@@ -289,20 +289,24 @@ class TestInputOutputMultilineMode(unittest.TestCase):
         """Test that Unicode messages are properly converted to ASCII with replacement"""
         io = InputOutput(pretty=False, fancy_input=False)
 
-        # Create a message with Unicode characters
+        # Create a message with invalid Unicode that can't be encoded in UTF-8
-        unicode_message = "Hello こんにちは Привет"
+        # Using a surrogate pair that's invalid in UTF-8
+        invalid_unicode = "Hello \ud800World"
 
         # Mock console.print to capture the output
         with patch.object(io.console, "print") as mock_print:
-            io._tool_message(unicode_message)
+            # First call will raise UnicodeEncodeError
+            mock_print.side_effect = [UnicodeEncodeError('utf-8', '', 0, 1, 'invalid'), None]
+            
+            io._tool_message(invalid_unicode)
 
             # Verify that the message was converted to ASCII with replacement
-            mock_print.assert_called_once()
+            self.assertEqual(mock_print.call_count, 2)
             args, kwargs = mock_print.call_args
             converted_message = args[0]
 
-            # The Unicode characters should be replaced with '?'
+            # The invalid Unicode should be replaced with '?'
-            self.assertEqual(converted_message, "Hello ????? ?????")
+            self.assertEqual(converted_message, "Hello ?World")
 
 
 if __name__ == "__main__":