gh-111138: Test the public PyList C API

Lib/test/test_capi/test_list.py

@@ -0,0 +1,233 @@
+import unittest
+from collections import UserList
+import _testcapi
+
+
+NULL = None
+PY_SSIZE_T_MIN = _testcapi.PY_SSIZE_T_MIN
+PY_SSIZE_T_MAX = _testcapi.PY_SSIZE_T_MAX
+
+PyList_Check = _testcapi.list_check
+PyList_CheckExact = _testcapi.list_checkexact
+PyList_Size = _testcapi.list_size
+PyList_GetItem = _testcapi.list_getitem
+PyList_SetItem = _testcapi.list_setitem
+PyList_Insert = _testcapi.list_insert
+PyList_Append = _testcapi.list_append
+PyList_Sort = _testcapi.list_sort
+PyList_AsTuple = _testcapi.list_astuple
+PyList_Reverse = _testcapi.list_reverse
+PyList_GetSlice = _testcapi.list_getslice
+PyList_SetSlice = _testcapi.list_setslice
+
+
+class ListSubclass(list):
+    pass
+
+
+class CAPITest(unittest.TestCase):
+
+    def test_list_check(self):
+        self.assertTrue(PyList_Check([2, 3, 5]))
+        # CRASHES self.assertFalse(PyList_Check(NULL))
+
+    def test_list_checkexact(self):
+        self.assertTrue(PyList_CheckExact([2, 3, 5]))
+        # CRASHES self.assertFalse(PyList_CheckExact(NULL))
+
+    def test_list_new(self):
+        expected = [None, None, None]
+
+        PyList_New = _testcapi.list_new
+        lst = PyList_New(3)
+        self.assertEqual(lst, expected)
+        self.assertIs(type(lst), list)
+        lst2 = PyList_New(3)
+        self.assertIsNot(lst2, lst)
+
+        with self.assertRaises(SystemError):
+            PyList_New(-1)
+
+    def test_list_size(self):
+        self.assertEqual(PyList_Size([]), 0)
+        self.assertEqual(PyList_Size([2, 3, 5]), 3)
+
+    def test_list_getitem(self):
+        lst = list("abc")
+        self.assertEqual(PyList_GetItem(lst, 0), "a")
+        self.assertEqual(PyList_GetItem(lst, 1), "b")
+        self.assertEqual(PyList_GetItem(lst, 2), "c")
+
+        for invalid_index in (PY_SSIZE_T_MIN, -1, len(lst), 10, PY_SSIZE_T_MAX):
+            with self.subTest(invalid_index=invalid_index):
+                self.assertRaises(IndexError, PyList_GetItem, lst, invalid_index)
+
+        lst2 = ListSubclass(lst)
+        self.assertEqual(PyList_GetItem(lst2, 1), "b")
+        self.assertRaises(IndexError, PyList_GetItem, lst2, len(lst2))
+
+        # CRASHES PyList_GetItem(NULL, 0)
+
+    def test_list_setitem(self):
+        lst = list("abc")
+        PyList_SetItem(lst, 1, "X")
+        self.assertEqual(lst, ["a", "X", "c"])
+        self.assertRaises(IndexError, PyList_SetItem, lst, 3, "Y")
+
+        lst2 = ListSubclass(list("abc"))
+        PyList_SetItem(lst2, 1, "X")
+        self.assertEqual(lst2, ["a", "X", "c"])
+
+        # CRASHES PyList_SetItem(list("abc"), 0, NULL)
+        # CRASHES PyList_SetItem(NULL, 0, 'x')
+
+    def test_list_insert(self):
+        lst = list("abc")
+        PyList_Insert(lst, 1, "X")
+        self.assertEqual(lst, ["a", "X", "b", "c"])
+        PyList_Insert(lst, -1, "Y")
+        self.assertEqual(lst, ["a", "X", "b", "Y", "c"])
+        PyList_Insert(lst, 100, "Z")
+        self.assertEqual(lst, ["a", "X", "b", "Y", "c", "Z"])
+        PyList_Insert(lst, -100, "0")
+        self.assertEqual(lst, ["0", "a", "X", "b", "Y", "c", "Z"])
+
+        lst2 = ListSubclass(list("abc"))
+        PyList_Insert(lst2, 1, "X")
+        self.assertEqual(lst2, ["a", "X", "b", "c"])
+
+        with self.assertRaises(SystemError):
+            PyList_Insert(list("abc"), 0, NULL)
+
+        # CRASHES PyList_Insert(NULL, 0, 'x')
+
+    def test_list_append(self):
+        lst = []
+        PyList_Append(lst, "a")
+        self.assertEqual(lst, ["a"])
+        PyList_Append(lst, "b")
+        self.assertEqual(lst, ["a", "b"])
+
+        lst2 = ListSubclass()
+        PyList_Append(lst2, "X")
+        self.assertEqual(lst2, ["X"])
+
+        self.assertRaises(SystemError, PyList_Append, [], NULL)
+
+        # CRASHES PyList_Append(NULL, 'a')
+
+    def test_list_sort(self):
+        lst = [4, 6, 7, 3, 1, 5, 9, 2, 0, 8]
+        PyList_Sort(lst)
+        self.assertEqual(lst, list(range(10)))
+
+        lst2 = ListSubclass([4, 6, 7, 3, 1, 5, 9, 2, 0, 8])
+        PyList_Sort(lst2)
+        self.assertEqual(lst2, list(range(10)))
+
+        with self.assertRaises(SystemError):
+            PyList_Sort(NULL)
+
+    def test_list_astuple(self):
+        self.assertEqual(PyList_AsTuple([]), ())
+        self.assertEqual(PyList_AsTuple([2, 5, 10]), (2, 5, 10))
+
+        with self.assertRaises(SystemError):
+            PyList_AsTuple(NULL)
+
+    def test_list_reverse(self):
+        def list_reverse(lst):
+            self.assertEqual(PyList_Reverse(lst), 0)
+            return lst
+
+        self.assertEqual(list_reverse([]), [])
+        self.assertEqual(list_reverse([2, 5, 10]), [10, 5, 2])
+
+        with self.assertRaises(SystemError):
+            PyList_Reverse(NULL)
+
+    def test_list_getslice(self):
+        lst = list("abcdef")
+
+        # empty
+        self.assertEqual(PyList_GetSlice(lst, -100, 0), [])
+        self.assertEqual(PyList_GetSlice(lst, 0, 0), [])
+        self.assertEqual(PyList_GetSlice(lst, 3, 0), [])
+
+        # slice
+        self.assertEqual(PyList_GetSlice(lst, 1, 3), list("bc"))
+
+        # whole
+        self.assertEqual(PyList_GetSlice(lst, 0, len(lst)), lst)
+        self.assertEqual(PyList_GetSlice(lst, 0, 100), lst)
+        self.assertEqual(PyList_GetSlice(lst, -100, 100), lst)
+
+        # CRASHES PyList_GetSlice(NULL, 0, 0)
+
+    def test_list_setslice(self):
+        def set_slice(lst, low, high, value):
+            lst = lst.copy()
+            self.assertEqual(PyList_SetSlice(lst, low, high, value), 0)
+            return lst
+
+        # insert items
+        self.assertEqual(set_slice([], 0, 0, list("abc")), list("abc"))
+        lst = list("abc")
+        self.assertEqual(set_slice(lst, 0, 0, ["X"]), list("Xabc"))
+        self.assertEqual(set_slice(lst, 1, 1, list("XY")), list("aXYbc"))
+        self.assertEqual(set_slice(lst, len(lst), len(lst), ["X"]), list("abcX"))
+        self.assertEqual(set_slice(lst, 100, 100, ["X"]), list("abcX"))
+
+        # replace items
+        lst = list("abc")
+        self.assertEqual(set_slice(lst, -100, 1, list("X")), list("Xbc"))
+        self.assertEqual(set_slice(lst, 1, 2, list("X")), list("aXc"))
+        self.assertEqual(set_slice(lst, 1, 3, list("XY")), list("aXY"))
+        self.assertEqual(set_slice(lst, 0, 3, list("XYZ")), list("XYZ"))
+
+        # delete items
+        lst = list("abcdef")
+        self.assertEqual(set_slice(lst, 0, len(lst), []), [])
+        self.assertEqual(set_slice(lst, -100, 100, []), [])
+        self.assertEqual(set_slice(lst, 1, 5, []), list("af"))
+        self.assertEqual(set_slice(lst, 3, len(lst), []), list("abc"))
+
+        # delete items with NULL
+        lst = list("abcdef")
+        self.assertEqual(set_slice(lst, 0, len(lst), NULL), [])
+        self.assertEqual(set_slice(lst, 3, len(lst), NULL), list("abc"))
+
+        # CRASHES PyList_SetSlice(NULL, 0, 0, ["x"])
+
+    def test_not_list_objects(self):
+        for obj in (
+            123,
+            UserList([2, 3, 5]),
+            (2, 3, 5),  # tuple
+            object(),
+        ):
+            with self.subTest(obj=obj):
+                self.assertFalse(PyList_Check(obj))
+                self.assertFalse(PyList_CheckExact(obj))
+                with self.assertRaises(SystemError):
+                    PyList_Size(obj)
+                with self.assertRaises(SystemError):
+                    PyList_SetItem(obj, 0, "x")
+                with self.assertRaises(SystemError):
+                    PyList_Insert(obj, 0, "x")
+                with self.assertRaises(SystemError):
+                    PyList_Append(obj, "x")
+                with self.assertRaises(SystemError):
+                    PyList_Sort(obj)
+                with self.assertRaises(SystemError):
+                    PyList_AsTuple(obj)
+                with self.assertRaises(SystemError):
+                    PyList_Reverse(obj)
+                with self.assertRaises(SystemError):
+                    PyList_GetSlice(obj, 0, 1)
+                with self.assertRaises(SystemError):
+                    PyList_SetSlice(obj, 0, 1, ["x"])
+
+
+if __name__ == "__main__":
+    unittest.main()