Build breakage in linux-next

It depends a lot what the objective of your testing is - shipping a product on -next is obviously silly, but if what you're doing is trying to ensure that what comes down the pipeline to your production systems is in reasonable shape then -next is a great place to do testing, you'll tend to catch things much closer to when they're introduced and therefore find it a lot easier to get things looked into. There's limits on what you'd want to test but it's valuable to pay attention. Similarly if what you're testing is functionality you use as opposed to functionality you write it doesn't really matter who introduced issues, you just want to find them and fix them.

For example I run testing of -next not so much because it's the thing I directly want to use but more because each merge window it turns into the baseline I'm testing against so if any of the boards or tests I rely on break then I'd much rather catch that while it's not impacting the testing I'm actually trying to do.