Process issue. Fix:
1. Write tests
2. Ensure tests can run in a well defined/containerized environment so that they can run tests and ensure they pass
* Are their code reviews _of you_ poor in particular, or are they poor in general when reviewing anyone's code?
* Are they reviewing your code in good faith (and are just finding it challenging) or in bad faith (and can't be arsed or don't like you / the project / etc)?
* Have you had a direct conversation with them about it? (Is your relationship with them strong enough to enable that?)
* Do your team have standards for a code review? Expectations for an author and for a reviewer?
Barring that... is there any way you can route your PR reviews to someone else?