https://hg.mozilla.org/integration/mozilla-inbound/rev/a13c1f26e351#l32.12 lead to https://treeherder.mozilla.org/logviewer.html#?job_id=12739111&repo=mozilla-inbound

Any idea what might be going on here, Chris?

We copy the binaries to $(DIST)/cppunittests as they're built, but we never delete anything from there: https://dxr.mozilla.org/mozilla-central/rev/d6ea652c579992daa9041cc9718bb7c6abefbc91/config/rules.mk#78 We could probably do something smarter here, like write out the list of CPP_UNIT_TESTS during backend generation and then during packaging copy just those files into the test package.

cppunitttests got some manifest support recently. Assuming that's wired up correctly removing the test from its manifest would help this situation too.