Get undefined report test is failing

Function `test_get_file_undefined` in `tests/test_process_interface.py` is failing and marked as skipped for now.

Not sure if this is generic functionality change or specific to this particular process.

Available file types for this process:

```python
['Unit Process', 'Life Cycle Inventory', 'Life Cycle Impact Assessment', 'Dataset Report']
```

Start with test_get_file_undefined in tests/test_process_interface.py and run the skipped test to reproduce the failure. Compare the expected undefined-file behavior with the listed process file types; done means the test has a clear, passing behavior rather than remaining skipped.

Written by the indexing model from the issue text.