141 lines
5.2 KiB
Python
141 lines
5.2 KiB
Python
#!/usr/bin/env python
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import networkx as nx
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class TestDFS:
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@classmethod
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def setup_class(cls):
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# simple graph
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G = nx.Graph()
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G.add_edges_from([(0, 1), (1, 2), (1, 3), (2, 4), (3, 4)])
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cls.G = G
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# simple graph, disconnected
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D = nx.Graph()
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D.add_edges_from([(0, 1), (2, 3)])
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cls.D = D
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def test_preorder_nodes(self):
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assert (list(nx.dfs_preorder_nodes(self.G, source=0)) ==
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[0, 1, 2, 4, 3])
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assert list(nx.dfs_preorder_nodes(self.D)) == [0, 1, 2, 3]
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def test_postorder_nodes(self):
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assert (list(nx.dfs_postorder_nodes(self.G, source=0)) ==
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[3, 4, 2, 1, 0])
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assert list(nx.dfs_postorder_nodes(self.D)) == [1, 0, 3, 2]
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def test_successor(self):
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assert (nx.dfs_successors(self.G, source=0) ==
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{0: [1], 1: [2], 2: [4], 4: [3]})
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assert nx.dfs_successors(self.D) == {0: [1], 2: [3]}
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def test_predecessor(self):
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assert (nx.dfs_predecessors(self.G, source=0) ==
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{1: 0, 2: 1, 3: 4, 4: 2})
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assert nx.dfs_predecessors(self.D) == {1: 0, 3: 2}
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def test_dfs_tree(self):
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exp_nodes = sorted(self.G.nodes())
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exp_edges = [(0, 1), (1, 2), (2, 4), (4, 3)]
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# Search from first node
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T = nx.dfs_tree(self.G, source=0)
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assert sorted(T.nodes()) == exp_nodes
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assert sorted(T.edges()) == exp_edges
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# Check source=None
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T = nx.dfs_tree(self.G, source=None)
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assert sorted(T.nodes()) == exp_nodes
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assert sorted(T.edges()) == exp_edges
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# Check source=None is the default
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T = nx.dfs_tree(self.G)
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assert sorted(T.nodes()) == exp_nodes
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assert sorted(T.edges()) == exp_edges
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def test_dfs_edges(self):
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edges = nx.dfs_edges(self.G, source=0)
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assert list(edges) == [(0, 1), (1, 2), (2, 4), (4, 3)]
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edges = nx.dfs_edges(self.D)
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assert list(edges) == [(0, 1), (2, 3)]
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def test_dfs_labeled_edges(self):
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edges = list(nx.dfs_labeled_edges(self.G, source=0))
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forward = [(u, v) for (u, v, d) in edges if d == 'forward']
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assert forward == [(0, 0), (0, 1), (1, 2), (2, 4), (4, 3)]
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def test_dfs_labeled_disconnected_edges(self):
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edges = list(nx.dfs_labeled_edges(self.D))
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forward = [(u, v) for (u, v, d) in edges if d == 'forward']
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assert forward == [(0, 0), (0, 1), (2, 2), (2, 3)]
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def test_dfs_tree_isolates(self):
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G = nx.Graph()
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G.add_node(1)
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G.add_node(2)
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T = nx.dfs_tree(G, source=1)
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assert sorted(T.nodes()) == [1]
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assert sorted(T.edges()) == []
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T = nx.dfs_tree(G, source=None)
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assert sorted(T.nodes()) == [1, 2]
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assert sorted(T.edges()) == []
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class TestDepthLimitedSearch:
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@classmethod
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def setup_class(cls):
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# a tree
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G = nx.Graph()
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nx.add_path(G, [0, 1, 2, 3, 4, 5, 6])
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nx.add_path(G, [2, 7, 8, 9, 10])
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cls.G = G
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# a disconnected graph
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D = nx.Graph()
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D.add_edges_from([(0, 1), (2, 3)])
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nx.add_path(D, [2, 7, 8, 9, 10])
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cls.D = D
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def dls_test_preorder_nodes(self):
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assert list(nx.dfs_preorder_nodes(self.G, source=0,
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depth_limit=2)) == [0, 1, 2]
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assert list(nx.dfs_preorder_nodes(self.D, source=1,
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depth_limit=2)) == ([1, 0])
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def dls_test_postorder_nodes(self):
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assert list(nx.dfs_postorder_nodes(self.G,
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source=3, depth_limit=3)) == [1, 7, 2, 5, 4, 3]
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assert list(nx.dfs_postorder_nodes(self.D,
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source=2, depth_limit=2)) == ([3, 7, 2])
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def dls_test_successor(self):
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result = nx.dfs_successors(self.G, source=4, depth_limit=3)
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assert ({n: set(v) for n, v in result.items()} ==
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{2: {1, 7}, 3: {2}, 4: {3, 5}, 5: {6}})
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result = nx.dfs_successors(self.D, source=7, depth_limit=2)
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assert ({n: set(v) for n, v in result.items()} ==
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{8: {9}, 2: {3}, 7: {8, 2}})
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def dls_test_predecessor(self):
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assert (nx.dfs_predecessors(self.G, source=0, depth_limit=3) ==
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{1: 0, 2: 1, 3: 2, 7: 2})
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assert (nx.dfs_predecessors(self.D, source=2, depth_limit=3) ==
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{8: 7, 9: 8, 3: 2, 7: 2})
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def test_dls_tree(self):
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T = nx.dfs_tree(self.G, source=3, depth_limit=1)
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assert sorted(T.edges()) == [(3, 2), (3, 4)]
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def test_dls_edges(self):
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edges = nx.dfs_edges(self.G, source=9, depth_limit=4)
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assert list(edges) == [(9, 8), (8, 7),
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(7, 2), (2, 1), (2, 3), (9, 10)]
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def test_dls_labeled_edges(self):
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edges = list(nx.dfs_labeled_edges(self.G, source=5, depth_limit=1))
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forward = [(u, v) for (u, v, d) in edges if d == 'forward']
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assert forward == [(5, 5), (5, 4), (5, 6)]
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def test_dls_labeled_disconnected_edges(self):
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edges = list(nx.dfs_labeled_edges(self.G, source=6, depth_limit=2))
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forward = [(u, v) for (u, v, d) in edges if d == 'forward']
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assert forward == [(6, 6), (6, 5), (5, 4)]
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