two version of R2R are here HEAD master

1 files changed, 144 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/tests/test_bridges.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/tests/test_bridges.py
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+"""Unit tests for bridge-finding algorithms."""
+
+import pytest
+
+import networkx as nx
+
+
+class TestBridges:
+    """Unit tests for the bridge-finding function."""
+
+    def test_single_bridge(self):
+        edges = [
+            # DFS tree edges.
+            (1, 2),
+            (2, 3),
+            (3, 4),
+            (3, 5),
+            (5, 6),
+            (6, 7),
+            (7, 8),
+            (5, 9),
+            (9, 10),
+            # Nontree edges.
+            (1, 3),
+            (1, 4),
+            (2, 5),
+            (5, 10),
+            (6, 8),
+        ]
+        G = nx.Graph(edges)
+        source = 1
+        bridges = list(nx.bridges(G, source))
+        assert bridges == [(5, 6)]
+
+    def test_barbell_graph(self):
+        # The (3, 0) barbell graph has two triangles joined by a single edge.
+        G = nx.barbell_graph(3, 0)
+        source = 0
+        bridges = list(nx.bridges(G, source))
+        assert bridges == [(2, 3)]
+
+    def test_multiedge_bridge(self):
+        edges = [
+            (0, 1),
+            (0, 2),
+            (1, 2),
+            (1, 2),
+            (2, 3),
+            (3, 4),
+            (3, 4),
+        ]
+        G = nx.MultiGraph(edges)
+        assert list(nx.bridges(G)) == [(2, 3)]
+
+
+class TestHasBridges:
+    """Unit tests for the has bridges function."""
+
+    def test_single_bridge(self):
+        edges = [
+            # DFS tree edges.
+            (1, 2),
+            (2, 3),
+            (3, 4),
+            (3, 5),
+            (5, 6),  # The only bridge edge
+            (6, 7),
+            (7, 8),
+            (5, 9),
+            (9, 10),
+            # Nontree edges.
+            (1, 3),
+            (1, 4),
+            (2, 5),
+            (5, 10),
+            (6, 8),
+        ]
+        G = nx.Graph(edges)
+        assert nx.has_bridges(G)  # Default root
+        assert nx.has_bridges(G, root=1)  # arbitrary root in G
+
+    def test_has_bridges_raises_root_not_in_G(self):
+        G = nx.Graph()
+        G.add_nodes_from([1, 2, 3])
+        with pytest.raises(nx.NodeNotFound):
+            nx.has_bridges(G, root=6)
+
+    def test_multiedge_bridge(self):
+        edges = [
+            (0, 1),
+            (0, 2),
+            (1, 2),
+            (1, 2),
+            (2, 3),
+            (3, 4),
+            (3, 4),
+        ]
+        G = nx.MultiGraph(edges)
+        assert nx.has_bridges(G)
+        # Make every edge a multiedge
+        G.add_edges_from([(0, 1), (0, 2), (2, 3)])
+        assert not nx.has_bridges(G)
+
+    def test_bridges_multiple_components(self):
+        G = nx.Graph()
+        nx.add_path(G, [0, 1, 2])  # One connected component
+        nx.add_path(G, [4, 5, 6])  # Another connected component
+        assert list(nx.bridges(G, root=4)) == [(4, 5), (5, 6)]
+
+
+class TestLocalBridges:
+    """Unit tests for the local_bridge function."""
+
+    @classmethod
+    def setup_class(cls):
+        cls.BB = nx.barbell_graph(4, 0)
+        cls.square = nx.cycle_graph(4)
+        cls.tri = nx.cycle_graph(3)
+
+    def test_nospan(self):
+        expected = {(3, 4), (4, 3)}
+        assert next(nx.local_bridges(self.BB, with_span=False)) in expected
+        assert set(nx.local_bridges(self.square, with_span=False)) == self.square.edges
+        assert list(nx.local_bridges(self.tri, with_span=False)) == []
+
+    def test_no_weight(self):
+        inf = float("inf")
+        expected = {(3, 4, inf), (4, 3, inf)}
+        assert next(nx.local_bridges(self.BB)) in expected
+        expected = {(u, v, 3) for u, v in self.square.edges}
+        assert set(nx.local_bridges(self.square)) == expected
+        assert list(nx.local_bridges(self.tri)) == []
+
+    def test_weight(self):
+        inf = float("inf")
+        G = self.square.copy()
+
+        G.edges[1, 2]["weight"] = 2
+        expected = {(u, v, 5 - wt) for u, v, wt in G.edges(data="weight", default=1)}
+        assert set(nx.local_bridges(G, weight="weight")) == expected
+
+        expected = {(u, v, 6) for u, v in G.edges}
+        lb = nx.local_bridges(G, weight=lambda u, v, d: 2)
+        assert set(lb) == expected