import torch

from torch_geometric.data import Data
from torch_geometric.transforms import TwoHop


def test_two_hop():
    transform = TwoHop()
    assert str(transform) == 'TwoHop()'

    edge_index = torch.tensor([[0, 0, 0, 1, 2, 3], [1, 2, 3, 0, 0, 0]])
    edge_attr = torch.tensor([1, 2, 3, 1, 2, 3], dtype=torch.float)
    data = Data(edge_index=edge_index, edge_attr=edge_attr, num_nodes=4)

    data = transform(data)
    assert len(data) == 3
    assert data.edge_index.equal(
        torch.tensor([
            [0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3],
            [1, 2, 3, 0, 2, 3, 0, 1, 3, 0, 1, 2],
        ]))
    assert data.edge_attr.equal(
        torch.tensor([1, 2, 3, 1, 0, 0, 2, 0, 0, 3, 0, 0]))
    assert data.num_nodes == 4

    data = Data(edge_index=edge_index, num_nodes=4)
    data = transform(data)
    assert len(data) == 2
    assert data.edge_index.equal(
        torch.tensor([
            [0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3],
            [1, 2, 3, 0, 2, 3, 0, 1, 3, 0, 1, 2],
        ]))
    assert data.num_nodes == 4