56 lines
1.5 KiB
Python
56 lines
1.5 KiB
Python
import networkx as nx
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def test_unionfind():
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# Fixed by: 2cddd5958689bdecdcd89b91ac9aaf6ce0e4f6b8
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# Previously (in 2.x), the UnionFind class could handle mixed types.
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# But in Python 3.x, this causes a TypeError such as:
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# TypeError: unorderable types: str() > int()
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#
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# Now we just make sure that no exception is raised.
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x = nx.utils.UnionFind()
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x.union(0, "a")
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def test_subtree_union():
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# See https://github.com/networkx/networkx/pull/3224
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# (35db1b551ee65780794a357794f521d8768d5049).
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# Test if subtree unions hare handled correctly by to_sets().
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uf = nx.utils.UnionFind()
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uf.union(1, 2)
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uf.union(3, 4)
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uf.union(4, 5)
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uf.union(1, 5)
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assert list(uf.to_sets()) == [{1, 2, 3, 4, 5}]
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def test_unionfind_weights():
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# Tests if weights are computed correctly with unions of many elements
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uf = nx.utils.UnionFind()
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uf.union(1, 4, 7)
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uf.union(2, 5, 8)
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uf.union(3, 6, 9)
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uf.union(1, 2, 3, 4, 5, 6, 7, 8, 9)
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assert uf.weights[uf[1]] == 9
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def test_unbalanced_merge_weights():
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# Tests if the largest set's root is used as the new root when merging
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uf = nx.utils.UnionFind()
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uf.union(1, 2, 3)
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uf.union(4, 5, 6, 7, 8, 9)
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assert uf.weights[uf[1]] == 3
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assert uf.weights[uf[4]] == 6
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largest_root = uf[4]
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uf.union(1, 4)
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assert uf[1] == largest_root
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assert uf.weights[largest_root] == 9
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def test_empty_union():
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# Tests if a null-union does nothing.
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uf = nx.utils.UnionFind((0, 1))
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uf.union()
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assert uf[0] == 0
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assert uf[1] == 1
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