#8 Raise value errors for empty inputs in to_awk. Added related tests

Author: ArturU043

servicex_analysis_utils/materialization.py

@@ -47,9 +47,14 @@ def to_awk(deliver_dict, dask=False, iterator=False, **kwargs):
         dict: keys are sample names and values are awkward arrays, uproot generator objects or dask-awkward arrays.
     """
 
+    if not deliver_dict:
+        raise ValueError("Input dict from servicex.deliver cannot be empty.")
+
     awk_arrays = {}
 
     for sample, paths in deliver_dict.items():
+        if not paths:
+            raise ValueError(f"ServiceX result path list for {sample} cannot be empty.")
         # Check file type
         f_type = str(paths[0])
         if ".root" in f_type:

tests/test_materialization.py

@@ -159,3 +159,19 @@ def test_unsupported_file_format():
         match=r"Unsupported file format: 'invalid_file.txt'\. Files must be ROOT \(.*\) or Parquet \(.*\)",
     ):
         to_awk(fake_paths)
+
+
+def test_empty_deliver_dict():
+    empty_dict = {}
+    with pytest.raises(
+        ValueError, match="Input dict from servicex.deliver cannot be empty."
+    ):
+        to_awk(empty_dict)
+
+
+def test_deliver_dict_empty_paths():
+    empty_dict = {"empty-Sample": []}
+    with pytest.raises(
+        ValueError, match="ServiceX result path list for empty-Sample cannot be empty."
+    ):
+        to_awk(empty_dict)