Keep selected camel-case OGC properties in normalized results

dataretrieval/ogc/shaping.py

@@ -230,8 +230,9 @@ def _arrange_cols(
     df : pd.DataFrame
         The input DataFrame whose columns are to be rearranged or renamed.
     properties : Optional[List[str]]
-        A list of column names to possibly rename. If None or contains
-        only NaN, the function renames 'id' to output_id.
+        Requested column names. Camel-case names are matched to normalized
+        snake_case DataFrame columns. If None or contains only NaN, the
+        function renames 'id' to output_id.
     output_id : str
         The name to which the 'id' column should be renamed if applicable.
     extra_id_cols : set or frozenset, optional
@@ -261,7 +262,10 @@ def _arrange_cols(
 
     # --- Explicit properties: select and reorder columns per the list ---
     # Do not alias the caller's list; it is mutated below.
-    local_properties = list(properties)
+    # Match the names normalized by _finalize_ogc before selecting columns.
+    local_properties = [
+        _to_snake_case(name) if isinstance(name, str) else name for name in properties
+    ]
     if "geometry" in df.columns and "geometry" not in local_properties:
         local_properties.append("geometry")
     # 'id' is a valid collection column, but expose it under the

tests/waterdata_utils_test.py

@@ -239,6 +239,31 @@ def test_finalize_ogc_truncates_combined_to_max_rows():
     assert hasattr(md, "url")  # wrapped as BaseMetadata
 
 
+def test_finalize_ogc_keeps_requested_camel_case_property():
+    """A selected API property remains in the normalized result frame."""
+    frame = pd.DataFrame(
+        {"id": ["obs-1"], "sampleTime": ["2024-01-01T00:00:00Z"], "value": [1.0]}
+    )
+    response = mock.MagicMock()
+    response.url = "https://example.com/collections/things/items"
+    response.elapsed = datetime.timedelta(seconds=0.1)
+    response.headers = {}
+    properties = ["sampleTime"]
+
+    result, _ = _finalize_ogc(
+        frame,
+        response,
+        properties=properties,
+        output_id="thing_id",
+        convert_type=False,
+        collection="things",
+    )
+
+    assert result.columns.tolist() == ["sample_time"]
+    assert result["sample_time"].tolist() == ["2024-01-01T00:00:00Z"]
+    assert properties == ["sampleTime"]
+
+
 def _resp_ok(features):
     """Build a 200-OK mock response with the given features list."""
     links = [{"rel": "next", "href": "https://example.com/page2"}] if features else []