test_path.py 文件源码

def combinable_paths_maybe_loops(draw):
    """Makes single-segment paths, with loops a possibility."""
    endpoints = draw(lists(ipoints, min_size=2, max_size=200, unique_by=tuple))
    rand = draw(randoms())
    paths = set()
    point_use = collections.defaultdict(int)

    target_number = len(endpoints) / 3
    if target_number < 1:
        target_number = 1

    while len(paths) < target_number:
        # Choose two points at random from the possible endpoints, and make a
        # segment.
        a, b = rand.sample(endpoints, k=2)
        if (a, b) in paths:
            continue
        paths.add((a, b))

        # Track how many times the points have been used.
        point_use[a] += 1
        point_use[b] += 1

        # Any point in two segments is no longer a candidate as an endpoint.
        if point_use[a] == 2:
            endpoints.remove(a)
        if point_use[b] == 2:
            endpoints.remove(b)

    return [Path(p) for p in paths]