This could maybe be a bug report too, but it doesn’t seem “broken” just confusing.
I quickly amended a commit after pushing it and before Circle had checked it out, which changed the hash. I promptly got an email and build status badge that said “No tests”, which was pretty alarming:
In reality, this branch has tests, it’s just that the checkout failed: https://cloudup.com/ilMvxkkkkm9
I’d consider the “Build failed” notification to be more useful here.