def test_neighbours():
_graph = Graph()
_node1 = Node(4)
_node2 = Node(5)
_node3 = Node(6)
_node4 = Node(7)
_graph.add_edges(_node1, _node2, 1)
_graph.add_edges(_node3, _node4, 1)
_graph.add_edges(_node2, _node4, 1)
_graph.add_edges(_node1, _node2, 2)
_graph.add_edges(_node3, _node4, 2)
_graph.add_edges(_node2, _node4, 2)
assert _graph.neighbours(_node2) == ['n0', 'n3']
