BUG: Snappy checksum check

Author: JacobSMoller

pyiceberg/avro/codecs/snappy_codec.py

@@ -51,9 +51,9 @@ def compress(data: bytes) -> tuple[bytes, int]:
         @staticmethod
         def decompress(data: bytes) -> bytes:
             # Compressed data includes a 4-byte CRC32 checksum
-            data = data[0:-4]
+            checksum = data[-4:]  # store checksum before truncating data
+            data = data[0:-4]  # remove checksum from the data
             uncompressed = snappy.decompress(data)
-            checksum = data[-4:]
             SnappyCodec._check_crc32(uncompressed, checksum)
             return uncompressed