unit tests of buildbot.status.web.base.plural() method
unit tests of buildbot.status.web.base.abbreviate_age methid()
test running 'buildslave stop' with invalid basedir path
test running 'buildslave restart' with invalid basedir path
unit tests on 'buildslave upgrade' command

Test that older buildbot.tac files are updated correctly.
Test that modern buildbot.tac files are not changed.