feature/PI-546-etl_item_already_exists Add decode script & update test name

Author: megan-bower4

scripts/etl/decode_load.py

@@ -0,0 +1,55 @@
+"""
+A script that decodes the unprocessed file from the s3 folder input--load/
+
+You can provide the downloaded file path, and chosen decoded file destination.
+"""
+
+import json
+import pickle
+from collections import deque
+
+import lz4.frame
+
+
+def lz4_pickle_decode_and_save(file_path: str, output_file: str):
+    try:
+        # Read the compressed pickle data from the file
+        with open(file_path, "rb") as f:
+            compressed_data = f.read()
+
+        # Decompress the LZ4 data
+        decompressed_data = lz4.frame.decompress(compressed_data)
+
+        # Unpickle the decompressed data
+        decoded_data = pickle.loads(decompressed_data)
+
+        # If the data is wrapped in a deque, convert it to a list
+        if isinstance(decoded_data, deque):
+            decoded_data = list(decoded_data)
+
+        # Save the decoded data to a file
+        with open(output_file, "w") as json_file:
+            json.dump(decoded_data, json_file, indent=2, default=str)
+
+        print(f"Decoded transaction(s) saved to {output_file}")  # noqa
+
+        return decoded_data
+
+    except lz4.frame.LZ4FrameError as e:
+        print(f"LZ4 decompression error: {e}")  # noqa
+    except pickle.UnpicklingError as e:
+        print(f"Unpickling error: {e}")  # noqa
+    except FileNotFoundError:
+        print(f"File not found: {file_path}")  # noqa
+    except Exception as e:
+        print(f"An unexpected error occurred: {e}")  # noqa
+
+
+# Example usage
+if __name__ == "__main__":
+    # Provide your file path and output file path here
+    file_path = "unprocessed-11"
+    output_file = "decoded_transaction.json"
+
+    # Decode the data from the file and save it to JSON
+    decoded_deque = lz4_pickle_decode_and_save(file_path, output_file)