ctypes: Add a testcase for nested `_as_parameter_` lookup

[tomasr8]

A ctypes function can be called with custom objects if they define the _as_parameter_ attribute:

from ctypes import *

printf = CDLL('libc.so.6').printf

class MyString:
    _as_parameter_ = b"abc"

printf(b"String: %s\n", MyString())
# String: abc

The attribute is evaluated recursively so nested objects also work:

from ctypes import *

printf = CDLL('libc.so.6').printf

class Foo:
    _as_parameter_ = b"abc"

class MyString:
    _as_parameter_ = Foo()

printf(b"String: %s\n", MyString())
# String: abc

There is currently no test for this nested case so I think we should add one.

Linked PRs

• gh-107461 ctypes: Add a testcase for nested _as_parameter_ lookup #107462
• [3.12] gh-107461 ctypes: Add a testcase for nested _as_parameter_ lookup (GH-107462) #114858
• [3.11] gh-107461 ctypes: Add a testcase for nested _as_parameter_ lookup (GH-107462) #114859