test_encode_model_retriever() gets stuck while running on Windows

[ritugala]

When using Windows, pytest gets stuck on this test, and it remains stuck till I dont manually abort the command. @viswavi speculates that maybe Tevatron doesn't support windows - I havent personally debugged around much

[ritugala]

Also there are issues running this test as well: test_retrieve_dataset_dict_when_search_index_exists() because temporary_files in windows cannot be opened again: https://stackoverflow.com/questions/23212435/permission-denied-to-write-to-my-temporary-file
Resolving this could be as simple as adding "delete=False" into the NamedTemporaryFile function, but it comes with the tradeoff that these temporary files would then need to be manually deleted.