chore: import upstream snapshot with attribution

easygraph/functions/basic/tests/test_avg_degree.py

@@ -0,0 +1,41 @@
+import easygraph as eg
+import pytest
+
+from easygraph.functions.basic import average_degree
+
+
+def test_average_degree_basic():
+    G = eg.Graph()
+    G.add_edges_from([(1, 2), (2, 3)])
+    assert average_degree(G) == pytest.approx(4 / 3)
+
+
+def test_average_degree_empty_graph():
+    G = eg.Graph()
+    with pytest.raises(ZeroDivisionError):
+        average_degree(G)
+
+
+def test_average_degree_self_loop():
+    G = eg.Graph()
+    G.add_edge(1, 1)  # self-loop
+    # Self-loop counts as 2 towards degree of node 1
+    assert average_degree(G) == pytest.approx(2.0)
+
+
+def test_average_degree_with_isolated_node():
+    G = eg.Graph()
+    G.add_edges_from([(1, 2), (2, 3)])
+    G.add_node(4)  # isolated node
+    assert average_degree(G) == pytest.approx(1.0)
+
+
+def test_average_degree_directed_graph():
+    G = eg.DiGraph()
+    G.add_edges_from([(1, 2), (2, 3), (3, 1)])
+    assert average_degree(G) == pytest.approx(2.0)
+
+
+def test_average_degree_invalid_input():
+    with pytest.raises(AttributeError):
+        average_degree(None)