Code review comment for lp://staging/~julian-edwards/launchpad/build-queue-sizes-bug-609904

Thanks for the review Maris.

<bigjools> mars: thank you
<bigjools> mars: so, no, the doctest is absolutely not the right place for
that test but I don't have the time to convert that all to unit tests and I am
loathe to write a new unit test and not include the existing ones.

I'm happy to file a cleanup bug about it.