Add tests and changelog for simple_cycle

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Changed
 
 - Dropped support for Python 3.8 as it has now reached its end of life.
+- Added `Graph.simple_cycles()` to find simple cycles in the graph.
 
 ## [0.11.8] - 2024-10-25
 

pyproject.toml

@@ -8,7 +8,8 @@ requires = [
     # Workaround based on this commit:
     # https://github.com/harfbuzz/uharfbuzz/commit/9b607bd06fb17fcb4abe3eab5c4f342ad08309d7
     "setuptools>=64,<72.2.0; platform_python_implementation == 'PyPy'",
-    "setuptools>=64; platform_python_implementation != 'PyPy'"
+    "setuptools>=64; platform_python_implementation != 'PyPy'",
+    "cmake>=3.12"
 ]
 build-backend = "setuptools.build_meta"
 

src/_igraph/graphobject.c

@@ -7862,7 +7862,7 @@ PyObject *igraphmodule_Graph_simple_cycles(
   igraph_vector_int_list_destroy(&vertices);
 
   PyObject *results;
-  results = Py_BuildValue("(OO)", results_vertices_o, result_edges_o);
+  results = Py_BuildValue("(OO)", result_vertices_o, result_edges_o);
   return results;
 }
 

tests/test_cycles.py

@@ -30,6 +30,24 @@ def test_is_dag(self):
         g = Graph.Ring(10, directed=True, mutual=False)
         self.assertFalse(g.is_dag())
 
+    def test_simple_cycles(self):
+        g = Graph(
+            [
+                (0, 1),
+                (1, 2),
+                (2, 0),
+                (0, 0),
+                (0, 3),
+                (3, 4),
+                (4, 5),
+                (5, 0),
+            ]
+        )
+
+        vertices, edges = g.simple_cycles()
+        assert len(vertices) == 3
+        assert len(edges) == 3
+
     def test_fundamental_cycles(self):
         g = Graph(
             [