[GEMINI] Write unit tests for decoding.py

tests/test_decoding.py

@@ -0,0 +1,43 @@
+# tests/test_decoding.py
+from ctf.decoding import try_decode_metadata
+
+# {{{ test_try_decode_metadata_hex
+def test_try_decode_metadata_hex():
+    """
+    Verifies that try_decode_metadata successfully decodes standard hex string payloads.
+    """
+    # Hex encoding of "picoCTF{hex_flag_hint}"
+    hex_str = "7069636f4354467b6865785f666c61675f68696e747d"
+    res = try_decode_metadata(hex_str)
+    assert res.get("hex") == "picoCTF{hex_flag_hint}"
+# }}}
+
+# {{{ test_try_decode_metadata_base64
+def test_try_decode_metadata_base64():
+    """
+    Verifies that try_decode_metadata successfully decodes standard base64 string payloads.
+    """
+    # Base64 encoding of "flag{b64_metadata}"
+    b64_str = "ZmxhZ3tiNjRfbWV0YWRhdGF9"
+    res = try_decode_metadata(b64_str)
+    assert res.get("base64") == "flag{b64_metadata}"
+# }}}
+
+# {{{ test_try_decode_metadata_non_decodable
+def test_try_decode_metadata_non_decodable():
+    """
+    Verifies that try_decode_metadata returns empty results for invalid or non-printable payloads.
+    """
+    # Invalid characters
+    res_invalid = try_decode_metadata("invalid!characters")
+    assert not res_invalid
+
+    # Not even length for hex, not modulo 4 for base64
+    res_odd = try_decode_metadata("1")
+    assert not res_odd
+
+    # Non-printable decoded content (binary raw data)
+    # Hex: \x01\x02\x03\x04
+    res_binary = try_decode_metadata("01020304")
+    assert not res_binary
+# }}}