Correct the test that expects a full table function list

[robinskil]

Problem

GET /api/table-functions always answers with an empty list. DataFusion does not catalog table valued functions.

The code marks the endpoint deprecated. See beacon-server/beacon-server/src/axum/client/functions.rs:12.

The test expects read_parquet and read_csv in the list. The test fails.

Failed test

• test_introspection.py::test_table_functions_include_readers

Task

1. Change the test to assert an empty list.
2. Add a comment that names the table function reference in the documentation.
3. Run the file again.

Environment

Branch features/reimplement-atlas. Image beacon-integration:local.