gh-94808: add tests covering PySequence_[InPlace_]Repeat

Lib/test/test_capi/test_misc.py

@@ -496,6 +496,172 @@ def __delitem__(self, index):
  _testcapi.sequence_del_slice(mapping, 1, 3)
  self.assertEqual(mapping, {1: 'a', 2: 'b', 3: 'c'})
 
+ def test_sequence_repeat(self):
+ # Basic test:
+ sequence = [1, 2, 3]
+ repeated_sequence = _testcapi.sequence_repeat(sequence, 2)
+ self.assertEqual(repeated_sequence, [1, 2, 3, 1, 2, 3])
+ self.assertEqual(repeated_sequence, sequence * 2)
+ self.assertEqual(sequence, [1, 2, 3]) # it must not change
+
+ # Corner values:
+ sequence = [1, 2, 3]
+ for value, res in [
+ (0, []),
+ (1, [1, 2, 3]),
+ (-1, []),
+ ]:
+ repeated_sequence = _testcapi.sequence_repeat(sequence, value)
+ self.assertEqual(repeated_sequence, res)
+ self.assertEqual(repeated_sequence, sequence * value)
+ self.assertEqual(sequence, [1, 2, 3]) # it must not change
+
+ def test_sequence_repeat_subtypes(self):
+ # List subtype:
+ class CustomList(list): ...
+
+ sequence = CustomList(['a', 'b'])
+ repeated_sequence = _testcapi.sequence_repeat(sequence, 3)
+ self.assertEqual(repeated_sequence,
+ CustomList(['a', 'b', 'a', 'b', 'a', 'b']))
+ self.assertEqual(repeated_sequence, sequence * 3)
+ self.assertEqual(sequence, CustomList(['a', 'b']))
+
+ # Tuple subtype:
+ class CustomTuple(tuple): ...
+
+ sequence = CustomTuple(('a', 'b'))
+ repeated_sequence = _testcapi.sequence_repeat(sequence, 3)
+ self.assertEqual(repeated_sequence,
+ CustomTuple(('a', 'b', 'a', 'b', 'a', 'b')))
+ self.assertEqual(repeated_sequence, sequence * 3)
+ self.assertEqual(sequence, CustomTuple(('a', 'b')))
+
+ # String subtype:
+ class CustomStr(str): ...
+
+ sequence = CustomStr('abc')
+ repeated_sequence = _testcapi.sequence_repeat(sequence, 2)
+ self.assertEqual(repeated_sequence,
+ CustomStr('abcabc'))
+ self.assertEqual(repeated_sequence, sequence * 2)
+ self.assertEqual(sequence, CustomStr('abc'))
+
+ def test_sequence_repeat_errors(self):
+ # Corner case, custom subtype returns `NotImplemented`:
+ class CustomListWithNI(list):
+ def __mul__(self, other):
+ return NotImplemented
+
+ sequence = CustomListWithNI(['a', 'b'])
+ with self.assertRaises(TypeError):
+ _testcapi.sequence_repeat(sequence, 3)
+ self.assertEqual(sequence, CustomListWithNI(['a', 'b'])) # not changed
+
+ # Non-sequences do not work (even with `__mul__`):
+ class CustomTypeWithMul:
+ def __mul__(self, other):
+ return 5 # won't be called
+
+ not_sequence = CustomTypeWithMul()
+ with self.assertRaises(TypeError):
+ _testcapi.sequence_repeat(not_sequence, 1)
+
+ def test_sequence_inplace_repeat(self):
+ # Basic list test:
+ sequence = [1, 2, 3]
+ repeated_sequence = _testcapi.sequence_inplace_repeat(sequence, 2)
+ self.assertEqual(repeated_sequence, [1, 2, 3, 1, 2, 3])
+ self.assertEqual(repeated_sequence, sequence)
+ self.assertEqual(sequence, [1, 2, 3, 1, 2, 3]) # changed
+ sequence_copy = [1, 2, 3]
+ sequence_copy *= 2 # It is the same thing
+ self.assertEqual(repeated_sequence, sequence_copy)
+
+ # Basic tuple test:
+ sequence = (1, 2, 3)
+ repeated_sequence = _testcapi.sequence_inplace_repeat(sequence, 2)
+ self.assertEqual(repeated_sequence, (1, 2, 3, 1, 2, 3))
+ self.assertNotEqual(repeated_sequence, sequence)
+ self.assertEqual(sequence, (1, 2, 3)) # not changed
+ sequence *= 2
+ self.assertEqual(repeated_sequence, sequence)
+
+ # Basic string test:
+ sequence = 'abc'
+ repeated_sequence = _testcapi.sequence_inplace_repeat(sequence, 2)
+ self.assertEqual(repeated_sequence, 'abcabc')
+ self.assertNotEqual(repeated_sequence, sequence)
+ self.assertEqual(sequence, 'abc') # not changed
+ sequence *= 2
+ self.assertEqual(repeated_sequence, sequence)
+
+ # Corner values:
+ sequence = (1, 2, 3)
+ for value, res in [
+ (0, ()),
+ (1, (1, 2, 3)),
+ (-1, ()),
+ ]:
+ repeated_sequence = _testcapi.sequence_inplace_repeat(sequence,
+ value)
+ self.assertEqual(repeated_sequence, res)
+ self.assertEqual(repeated_sequence, sequence * value)
+ self.assertEqual(sequence, (1, 2, 3)) # tuple must not change
+
+ def test_sequence_inplace_repeat_subtypes(self):
+ # List subtype:
+ class CustomList(list): ...
+
+ sequence = CustomList(['a', 'b'])
+ repeated_sequence = _testcapi.sequence_inplace_repeat(sequence, 3)
+ self.assertEqual(repeated_sequence,
+ CustomList(['a', 'b', 'a', 'b', 'a', 'b']))
+ self.assertEqual(repeated_sequence, sequence)
+
+ # Tuple subtype:
+ class CustomTuple(tuple): ...
+
+ sequence = CustomTuple(('a', 'b'))
+ repeated_sequence = _testcapi.sequence_inplace_repeat(sequence, 3)
+ self.assertEqual(repeated_sequence,
+ CustomTuple(('a', 'b', 'a', 'b', 'a', 'b')))
+ self.assertEqual(repeated_sequence, sequence * 3)
+ self.assertEqual(sequence, CustomTuple(('a', 'b')))
+
+ # String subtype:
+ class CustomStr(str): ...
+
+ sequence = CustomStr('abc')
+ repeated_sequence = _testcapi.sequence_inplace_repeat(sequence, 2)
+ self.assertEqual(repeated_sequence, CustomStr('abcabc'))
+ self.assertEqual(repeated_sequence, sequence * 2)
+ self.assertEqual(sequence, CustomStr('abc'))
+
+ def test_sequence_inplace_repeat_errors(self):
+ # Corner case, custom subtype returns `NotImplemented`:
+ class CustomListWithNI(list):
+ def __mul__(self, other):
+ return NotImplemented
+ def __imul__(self, other):
+ return NotImplemented
+
+ sequence = CustomListWithNI(['a', 'b'])
+ with self.assertRaises(TypeError):
+ _testcapi.sequence_inplace_repeat(sequence, 3)
+ self.assertEqual(sequence, CustomListWithNI(['a', 'b'])) # not changed
+
+ # Non-sequences do not work (even with `__mul__` and `__imul__`):
+ class CustomTypeWithMul:
+ def __mul__(self, other):
+ return 0
+ def __imul__(self, other):
+ return 1 # won't be called
+
+ not_sequence = CustomTypeWithMul()
+ with self.assertRaises(TypeError):
+ _testcapi.sequence_inplace_repeat(not_sequence, 1)
+
  @unittest.skipUnless(hasattr(_testcapi, 'negative_refcount'),
  'need _testcapi.negative_refcount')
  def test_negative_refcount(self):

Modules/_testcapimodule.c

@@ -4829,6 +4829,30 @@ sequence_del_slice(PyObject* self, PyObject *args)
  Py_RETURN_NONE;
 }
 
+static PyObject *
+sequence_repeat(PyObject* self, PyObject *args)
+{
+ PyObject *sequence;
+ Py_ssize_t count;
+ if (!PyArg_ParseTuple(args, "On", &sequence, &count)) {
+ return NULL;
+ }
+
+ return PySequence_Repeat(sequence, count);
+}
+
+static PyObject *
+sequence_inplace_repeat(PyObject* self, PyObject *args)
+{
+ PyObject *sequence;
+ Py_ssize_t count;
+ if (!PyArg_ParseTuple(args, "On", &sequence, &count)) {
+ return NULL;
+ }
+
+ return PySequence_InPlaceRepeat(sequence, count);
+}
+
 static PyObject *
 test_pythread_tss_key_state(PyObject *self, PyObject *args)
 {
@@ -6376,6 +6400,8 @@ static PyMethodDef TestMethods[] = {
  {"mapping_has_key", mapping_has_key, METH_VARARGS},
  {"sequence_set_slice", sequence_set_slice, METH_VARARGS},
  {"sequence_del_slice", sequence_del_slice, METH_VARARGS},
+ {"sequence_repeat", sequence_repeat, METH_VARARGS},
+ {"sequence_inplace_repeat", sequence_inplace_repeat, METH_VARARGS},
  {"test_pythread_tss_key_state", test_pythread_tss_key_state, METH_VARARGS},
  {"hamt", new_hamt, METH_NOARGS},
  {"bad_get", _PyCFunction_CAST(bad_get), METH_FASTCALL},