[TASK] Add unit test to cover stdWrap_postUserFunc

Releases: master
Resolves: #76849
Change-Id: Ibf74561f5339deacf14f1d87038a56e49e98a9f0
Reviewed-on: https://review.typo3.org/48745


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Tested-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>