Function test_matrices_are_not_writeable

tests/test_ProblemData.py:434–458

Tests that the data matrices provided by ``distance_matrix()`` and ``duration_matrix()`` are not writeable. They can be read from, but assigning new values should raise an error. We require this because they're constant on the C++ side, and allowing changes from Python causes u

()

def test_matrices_are_not_writeable():
    """
    Tests that the data matrices provided by ``distance_matrix()`` and
    ``duration_matrix()`` are not writeable. They can be read from, but
    assigning new values should raise an error.

    We require this because they're constant on the C++ side, and allowing
    changes from Python causes undefined behaviour on the C++ side.
    """
    data = ProblemData(
        clients=[],
        depots=[Depot(x=0, y=0)],
        vehicle_types=[VehicleType(2)],
        distance_matrices=[np.array([[0]])],
        duration_matrices=[np.array([[0]])],
    )

    dist_mat = data.distance_matrix(profile=0)
    dur_mat = data.duration_matrix(profile=0)

    with assert_raises(ValueError):
        dist_mat[0, 0] = 1_000

    with assert_raises(ValueError):
        dur_mat[0, 0] = 1_000


def test_matrices_are_not_copies():