Hi, @robert jenkins
Thank you for posting in Microsoft Q&A forum.
I don't think you need to export the patches from one SCCM server and bring them to a test environment.
We may need to install WSUS and configure the SUP role in test environment like you do in the production environment.
Here is the steps to install WSUS, configure SUP and sync the updates:
https://www.prajwaldesai.com/install-wsus-for-sccm-sup-role-configmgr/
https://www.prajwaldesai.com/install-sccm-software-update-point-role/
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