[GEMINI] Add unit tests for recursive nested decoding

tests/test_decoding.py

@@ -100,4 +100,14 @@ def test_try_decode_metadata_reversed_only_flags():
     # Reversed of "normal text" -> "txet lamron"
     res_noise = try_decode_metadata("txet lamron")
     assert "reversed" not in res_noise
+# {{{ test_try_decode_metadata_nested
+def test_try_decode_metadata_nested():
+    """
+    Verifies that try_decode_metadata recursively decodes nested encodings and reports the path.
+    """
+    # Payload: base64(hex("flag{nested_flag}"))
+    nested_str = "NjY2YzYxNjc3YjZlNjU3Mzc0NjU2NDVmNjY2YzYxNjc3ZA=="
+    res = try_decode_metadata(nested_str)
+    assert res.get("base64") == "666c61677b6e65737465645f666c61677d"
+    assert res.get("base64->hex") == "flag{nested_flag}"
 # }}}