def test_channel_segment_add_upstream_node():
segment = ChannelSegment([0, 1])
upstream = ChannelSegment([5, 6])
assert len(segment.upstream) == 0
assert upstream.downstream is None
segment.add_upstream(upstream)
assert upstream in segment.upstream
assert upstream.downstream is segment
def test_reindex_segment_nodes_with_downstream(nodes, last_node):
root = ChannelSegment([0, 1])
segment = ChannelSegment(nodes)
root.add_upstream(segment)
reindex = SegmentNodeReindexer(nodes=[last_node])
reindex(segment)
assert segment.nodes[0] == root.nodes[-1]
assert segment.nodes[1:] == list(range(last_node + 1, last_node + len(nodes)))
def test_create_links_with_downstream(nodes):
root = ChannelSegment([0, 1])
segment = ChannelSegment(nodes)
root.add_upstream(segment)
collect_links = SegmentLinkCollector()
collect_links(segment)
links = collect_links.links
assert len(links) == len(segment) - 1
assert links[0] == (root.nodes[-1], segment.nodes[1])
if len(links) > 1:
heads, tails = zip(*links[1:])
assert list(heads) == nodes[1:-1]
assert list(tails) == nodes[2:]