[GEMINI] Add unit test for debug_exception_handler

tests/test_main.py

@@ -17,3 +17,22 @@ def test_main_entry_point_help():
         
         # Verify it exits with a successful exit code (0)
         assert exc_info.value.code == 0
+
+# {{{ test_debug_exception_handler
+def test_debug_exception_handler():
+    """
+    Verifies that debug_exception_handler prints traceback and invokes pdb.post_mortem.
+    """
+    from ctf.main import debug_exception_handler
+    from unittest.mock import patch, MagicMock
+    
+    mock_tb = MagicMock()
+    with patch("traceback.print_exception") as mock_print, \
+         patch("pdb.post_mortem") as mock_pm:
+         
+        debug_exception_handler(ValueError, ValueError("test error"), mock_tb)
+        
+        mock_print.assert_called_once_with(ValueError, ValueError("test error"), mock_tb)
+        mock_pm.assert_called_once_with(mock_tb)
+# }}}
+