import pytest

from qolab.file_utils import infer_compression

def test_infer_compression():
    assert infer_compression('data.dat') is None
    assert infer_compression('data.unknown_ext') is None
    assert infer_compression('data.dat.gz')  == 'gzip'
    assert infer_compression('data.dat.bz')  == 'bzip'
    assert infer_compression('data.dat.bz2') == 'bzip'