One of the unit tests (knn_retrieval) can fail (machine dependent?)

[escherba]

Describe the bug
A test that checks that the correct neighbors are retrieved fails. This could be a minor issue (perhaps 100% accuracy is not expected).

To Reproduce
Create a virtual environment using Annoy=0.17.0 and Ivis=2.0.1 (current master), then run pytest

Expected behavior
My PDB session in test_knn.py:69

(Pdb) mask = expected_neighbour_list != neighbour_list
(Pdb) p expected_neighbour_list[mask]
array([93])
(db) p neighbour_list[mask]
array([75])

[escherba]

Potentially wrong report, will reopen if persists