diff --git a/io_util.py b/io_util.py
index efb8f38..67d9049 100644
--- a/io_util.py
+++ b/io_util.py
@@ -217,10 +217,8 @@ def delete_input_file(input_file: str, source_id: str, actually_delete: bool) ->
     return True  # return True even if empty dirs were not removed
 
 
-def obtain_input_file(handler, doc: Document) -> VisXPFeatureExtractionInput:
-    # first fetch and validate the obtained S3 URI
-    # TODO make sure this is a valid S3 URI
-    s3_uri = _fetch_visxp_prep_s3_uri(handler, doc)
+def obtain_input_file(s3_uri: str) -> VisXPFeatureExtractionInput:
+
     if not validate_s3_uri(s3_uri):
         return VisXPFeatureExtractionInput(500, f"Invalid S3 URI: {s3_uri}")
 
@@ -231,9 +229,11 @@ def obtain_input_file(handler, doc: Document) -> VisXPFeatureExtractionInput:
     # TODO download the content into get_download_dir()
     s3 = S3Store(cfg.OUTPUT.S3_ENDPOINT_URL)
     bucket, object_name = parse_s3_uri(s3_uri)
+    logger.info(f"OBJECT NAME: {object_name}")
     input_file_path = os.path.join(
         get_download_dir(),
-        os.path.basename(object_name),  # source_id is part of the object_name
+        source_id,
+        os.path.basename(object_name),  # i.e. visxp_prep__<source_id>.tar.gz
     )
     success = s3.download_file(bucket, object_name, output_folder)
     if success:
@@ -258,7 +258,7 @@ def obtain_input_file(handler, doc: Document) -> VisXPFeatureExtractionInput:
     return VisXPFeatureExtractionInput(500, f"Failed to download: {s3_uri}")
 
 
-def _fetch_visxp_prep_s3_uri(handler, doc: Document) -> str:
+def fetch_visxp_prep_s3_uri(handler, doc: Document) -> str:
     logger.info("checking download worker output")
     possibles = handler.searchResult(doc._id, DANE_VISXP_PREP_TASK_KEY)
     logger.info(possibles)
diff --git a/worker.py b/worker.py
index ebc29e9..10a8def 100644
--- a/worker.py
+++ b/worker.py
@@ -7,10 +7,12 @@
 from dane import Document, Task, Result
 from dane.base_classes import base_worker
 from dane.config import cfg
+from dane.s3_util import validate_s3_uri
 from models import CallbackResponse, OutputType, Provenance, VisXPFeatureExtractionInput
 from io_util import (
     generate_output_dirs,
     get_source_id_from_tar,
+    fetch_visxp_prep_s3_uri,
     obtain_input_file,
     get_base_output_dir,
     get_download_dir,
@@ -35,13 +37,18 @@
 # triggered by running: python worker.py --run-test-file
 def process_configured_input_file() -> bool:
     logger.info("Triggered processing of configured VISXP_EXTRACT.TEST_INPUT_PATH")
-    feature_extraction_input = VisXPFeatureExtractionInput(
-        200,
-        f"Thank you for running us: let's test {cfg.VISXP_EXTRACT.TEST_INPUT_PATH}",
-        get_source_id_from_tar(cfg.VISXP_EXTRACT.TEST_INPUT_PATH),
-        cfg.VISXP_EXTRACT.TEST_INPUT_PATH,
-        None,  # no provenance needed in test
-    )
+
+    # S3 URI is also allowed for VISXP_EXTRACT.TEST_INPUT_PATH
+    if validate_s3_uri(cfg.VISXP_EXTRACT.TEST_INPUT_PATH):
+        feature_extraction_input = obtain_input_file(cfg.VISXP_EXTRACT.TEST_INPUT_PATH)
+    else:
+        feature_extraction_input = VisXPFeatureExtractionInput(
+            200,
+            f"Thank you for running us: let's test {cfg.VISXP_EXTRACT.TEST_INPUT_PATH}",
+            get_source_id_from_tar(cfg.VISXP_EXTRACT.TEST_INPUT_PATH),
+            cfg.VISXP_EXTRACT.TEST_INPUT_PATH,
+            None,  # no provenance needed in test
+        )
 
     # first generate the output dirs
     generate_output_dirs(feature_extraction_input.source_id)
@@ -178,9 +185,16 @@ def callback(self, task: Task, doc: Document) -> CallbackResponse:
             output_data={},
         )
 
-        # obtain the input file
-        # TODO make sure to download the output from S3
-        feature_extraction_input = obtain_input_file(self.handler, doc)
+        # fetch s3 uri of visxp_prep data:
+        s3_uri = fetch_visxp_prep_s3_uri(self.handler, doc)
+        if not s3_uri:
+            return {
+                "state": 404,
+                "message": "Could not find VISXP_PREP data",
+            }
+
+        # download the VISXP_PREP data via the S3 URI
+        feature_extraction_input = obtain_input_file(s3_uri)
         if not feature_extraction_input.state == 200:
             return {
                 "state": feature_extraction_input.state,