Comment 1 for bug 1435978

OK. This is resolved by upgrading to the latest testtools, which has many many fixes since the version currently available in debian/ubuntu.

Unfortunately, it requires updated unittest2 as well, and some other new dependencies which are not yet packaged. However, I've got some initial packaging for these, and the latest testtools, in ppa:dobey/testtools and it is working much more reliably for me now.