Previously, the generate-fixtures shell script by called into Django
multiple times in order to check whether the database was in a
reasonable state. Since there's a lot of overhead to starting up
Django, this resulted in `test-backend` and `test-js-with-casper`
being quite slow to run a single small test (2.8s or so) even on my
very fast laptop.
We fix this is by moving the checks into a new Python library, so that
we can avoid paying the Django startup overhead 3 times unnecessarily.
The result saves about 1.2s (~40%) from the time required to run a
single backend test.
Fixes#1221.
When running ./tools/test-backend, the script to generate
fixtures, ./tools/setup/generate-fixtures, looks for a file
called migration-status to determine whether it can short
circuit doing database migrations. This file got moved as
part of the effort to put files in "var," but the existence
check was still looking for that file in its old location.
Tim Abbott
Anders Kaseorg
Tomasz Kolek
Steve Howell
Taranjeet Singh
Umair Khan