test_topsort.py

from galaxy.util import topsort


def test_topsort_level_stability():
    data = [
        (0, 2),
        (1, 2),
        (2, 3),
        (2, 4),
        (3, 4),
        (3, 5),
    ]
    assert topsort.topsort( data ) == [ 0, 1, 2, 3, 4, 5 ]
    # Swap first two edges - so 1 appears first
    tmp = data[ 0 ]
    data[ 0 ] = data[ 1 ]
    data[ 1 ] = tmp
    assert topsort.topsort( data ) == [ 1, 0, 2, 3, 4, 5 ]
    # Above line fails...