First thought, "wat", what if the code is broken, not the tests...
Second thought, if the entire unit test file is getting generated by claude without significant oversight like this suggests... I suppose its probably the tests that are broken.
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As for your own situation. Looking for a new job because you aren't happy with the process at your current job is completely reasonable.
I'm not sure that you're right that this workflow will cause your technical growth to stall though - the freedom to experiment with strange new (probably ineffective) workflows on someone else's dime might well be beneficial in many ways. But if you're not happy doing this, and you have the skills and network to find a new job, why wouldn't you?