import torch

from torch_geometric.data import Data
from torch_geometric.transforms import FaceToEdge


def test_face_to_edge():
    transform = FaceToEdge()
    assert str(transform) == 'FaceToEdge()'

    face = torch.tensor([[0, 0], [1, 1], [2, 3]])
    data = Data(face=face, num_nodes=4)

    data = transform(data)
    assert len(data) == 2
    assert data.edge_index.tolist() == [[0, 0, 0, 1, 1, 1, 2, 2, 3, 3],
                                        [1, 2, 3, 0, 2, 3, 0, 1, 0, 1]]
    assert data.num_nodes == 4