Make sure that cli tests don't leave subcommands hanging
The current tests depend on order of execution: if the main tests run before the db tests, the addition of extra subcommands makes them fail.
Depends on !108 (closed) Depends on !107 (closed) (kinda)
Test Plan
tox -e py3-core-db
(running both core and db tests, in that order)
would fail before this diff
Migrated from D2330 (view on Phabricator)