cpython/Lib/test/test_ctypes/test_python_api.py

import _ctypes
import sys
import unittest
from test import support
from ctypes import (pythonapi, POINTER, create_string_buffer, sizeof,
                    py_object, c_char_p, c_char, c_long, c_size_t)


class PythonAPITestCase(unittest.TestCase):
    def test_PyBytes_FromStringAndSize(self):
        PyBytes_FromStringAndSize = pythonapi.PyBytes_FromStringAndSize

        PyBytes_FromStringAndSize.restype = py_object
        PyBytes_FromStringAndSize.argtypes = c_char_p, c_size_t

        self.assertEqual(PyBytes_FromStringAndSize(b"abcdefghi", 3), b"abc")

    @support.refcount_test
    def test_PyString_FromString(self):
        pythonapi.PyBytes_FromString.restype = py_object
        pythonapi.PyBytes_FromString.argtypes = (c_char_p,)

        s = b"abc"
        refcnt = sys.getrefcount(s)
        pyob = pythonapi.PyBytes_FromString(s)
        self.assertEqual(sys.getrefcount(s), refcnt)
        self.assertEqual(s, pyob)
        del pyob
        self.assertEqual(sys.getrefcount(s), refcnt)

    @support.refcount_test
    def test_PyLong_Long(self):
        ref42 = sys.getrefcount(42)
        pythonapi.PyLong_FromLong.restype = py_object
        self.assertEqual(pythonapi.PyLong_FromLong(42), 42)

        self.assertEqual(sys.getrefcount(42), ref42)

        pythonapi.PyLong_AsLong.argtypes = (py_object,)
        pythonapi.PyLong_AsLong.restype = c_long

        res = pythonapi.PyLong_AsLong(42)
        # Small int refcnts don't change
        self.assertEqual(sys.getrefcount(res), ref42)
        del res
        self.assertEqual(sys.getrefcount(42), ref42)

    @support.refcount_test
    def test_PyObj_FromPtr(self):
        s = object()
        ref = sys.getrefcount(s)
        # id(python-object) is the address
        pyobj = _ctypes.PyObj_FromPtr(id(s))
        self.assertIs(s, pyobj)

        self.assertEqual(sys.getrefcount(s), ref + 1)
        del pyobj
        self.assertEqual(sys.getrefcount(s), ref)

    def test_PyOS_snprintf(self):
        PyOS_snprintf = pythonapi.PyOS_snprintf
        PyOS_snprintf.argtypes = POINTER(c_char), c_size_t, c_char_p

        buf = create_string_buffer(256)
        PyOS_snprintf(buf, sizeof(buf), b"Hello from %s", b"ctypes")
        self.assertEqual(buf.value, b"Hello from ctypes")

        PyOS_snprintf(buf, sizeof(buf), b"Hello from %s (%d, %d, %d)", b"ctypes", 1, 2, 3)
        self.assertEqual(buf.value, b"Hello from ctypes (1, 2, 3)")

        # not enough arguments
        self.assertRaises(TypeError, PyOS_snprintf, buf)

    def test_pyobject_repr(self):
        self.assertEqual(repr(py_object()), "py_object(<NULL>)")
        self.assertEqual(repr(py_object(42)), "py_object(42)")
        self.assertEqual(repr(py_object(object)), "py_object(%r)" % object)


if __name__ == "__main__":
    unittest.main()