chore: import upstream snapshot with attribution

2026-07-13 12:36:30 +08:00
commit 55ab4e4a73
473 changed files with 72932 additions and 0 deletions
@@ -0,0 +1,79 @@
+import easygraph as eg
+import pytest
+
+
+class TestPredecessor:
+    # @classmethod
+    # def setup_class(self):
+    #     pytest.importskip("numpy")
+
+    def test_predecessor(self):
+        G = eg.path_graph(4)
+        for source in G:
+            assert eg.predecessor(G, source) in [
+                {0: [], 1: [0], 2: [1], 3: [2]},
+                {1: [], 0: [1], 2: [1], 3: [2]},
+                {2: [], 1: [2], 3: [2], 0: [1]},
+                {3: [], 2: [3], 1: [2], 0: [1]},
+            ]
+
+    def test_basic_predecessor(self):
+        G = eg.path_graph(4)
+        result = eg.predecessor(G, 0)
+        assert result == {0: [], 1: [0], 2: [1], 3: [2]}
+
+    def test_with_return_seen(self):
+        G = eg.path_graph(4)
+        pred, seen = eg.predecessor(G, 0, return_seen=True)
+        assert pred == {0: [], 1: [0], 2: [1], 3: [2]}
+        assert seen == {0: 0, 1: 1, 2: 2, 3: 3}
+
+    def test_with_target(self):
+        G = eg.path_graph(4)
+        assert eg.predecessor(G, 0, target=2) == [1]
+
+    def test_with_target_and_return_seen(self):
+        G = eg.path_graph(4)
+        pred, seen = eg.predecessor(G, 0, target=2, return_seen=True)
+        assert pred == [1]
+        assert seen == 2
+
+    def test_with_cutoff(self):
+        G = eg.path_graph(4)
+        pred = eg.predecessor(G, 0, cutoff=1)
+        assert pred == {0: [], 1: [0]}
+
+    def test_disconnected_graph(self):
+        G = eg.Graph()
+        G.add_edges_from([(0, 1), (2, 3)])
+        pred = eg.predecessor(G, 0)
+        assert 2 not in pred and 3 not in pred
+
+    def test_invalid_source(self):
+        G = eg.path_graph(4)
+        with pytest.raises(eg.NodeNotFound):
+            eg.predecessor(G, 99)
+
+    def test_no_path_to_target(self):
+        G = eg.Graph()
+        G.add_edges_from([(0, 1), (2, 3)])
+        assert eg.predecessor(G, 0, target=3) == []
+
+    def test_no_path_to_target_with_return_seen(self):
+        G = eg.Graph()
+        G.add_edges_from([(0, 1), (2, 3)])
+        pred, seen = eg.predecessor(G, 0, target=3, return_seen=True)
+        assert pred == []
+        assert seen == -1
+
+    def test_cycle_graph(self):
+        G = eg.Graph()
+        G.add_edges_from([(0, 1), (1, 2), (2, 3), (3, 0)])  # cycled graph
+        pred = eg.predecessor(G, 0)
+        assert set(pred.keys()) == set(G.nodes)
+
+    def test_directed_graph(self):
+        G = eg.DiGraph()
+        G.add_edges_from([(0, 1), (1, 2), (2, 3)])
+        pred = eg.predecessor(G, 0)
+        assert pred == {0: [], 1: [0], 2: [1], 3: [2]}