[issue39593] Adding a unit test of ctypes

[hai shi]

New submission from hai shi <shihai1991 at 126.com>:

strlen(data) can not be replaced by Py_SIZE(value) in https://github.com/python/cpython/blob/master/Modules/_ctypes/cfield.c#L1297.

victor have give a great example about it in https://github.com/python/cpython/pull/18419

I create this bpo for two reasons:
1. This question info could be removed(some questions info will catch my attention）
2. Current tests should be enhanced(It can not help me found this backward incompatible:( ).

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components: Tests
messages: 361656
nosy: shihai1991
priority: normal
severity: normal
status: open
title: Adding a unit test of ctypes
type: enhancement
versions: Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39593>
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