test_min_spanning_tree_prim.py

from collections import defaultdict

from graphs.minimum_spanning_tree_prims import prisms_algorithm as mst


def test_prim_successful_result():
    num_nodes, num_edges = 9, 14  # noqa: F841
    edges = [
        [0, 1, 4],
        [0, 7, 8],
        [1, 2, 8],
        [7, 8, 7],
        [7, 6, 1],
        [2, 8, 2],
        [8, 6, 6],
        [2, 3, 7],
        [2, 5, 4],
        [6, 5, 2],
        [3, 5, 14],
        [3, 4, 9],
        [5, 4, 10],
        [1, 7, 11],
    ]

    adjacency = defaultdict(list)
    for node1, node2, cost in edges:
        adjacency[node1].append([node2, cost])
        adjacency[node2].append([node1, cost])

    result = mst(adjacency)

    expected = [
        [7, 6, 1],
        [2, 8, 2],
        [6, 5, 2],
        [0, 1, 4],
        [2, 5, 4],
        [2, 3, 7],
        [0, 7, 8],
        [3, 4, 9],
    ]

    for answer in expected:
        edge = tuple(answer[:2])
        reverse = tuple(edge[::-1])
        assert edge in result or reverse in result