This change makes several improvements:
* Use in-memory SQLite database for test migrations
The default database is SQLite but its NAME (which SQLite uses as the
filename) was `wagtail`, which isn't valid since
the wagtail codebase already has a `wagtail/` directory. Trying to
run migration creation commands
(https://docs.wagtail.io/en/latest/contributing/developing.html#running-migrations-for-the-test-app-models)
produced an error:
django.db.utils.OperationalError: unable to open database file
because of this conflict.
This change uses an in-memory database as the default database for
tests. If DATABASE_NAME were set to a real file name, then
running the migration command with SQLite creates an empty db with
this filename on running `django-admin`.
Other non-SQLite engines continue to use the original `wagtail` name,
meaning that the `test_wagtail` database gets created just as before.
* Modifies the default values for database USER, PASSWORD, HOST etc to
being an empty string rather than None, to match Django's
[defaults](https://docs.djangoproject.com/en/stable/ref/settings/#host).
This helps avoid any potential issues when Django and database engines
are expecting this being a string.
* Adds documentation to `developing.rst` regarding installation of
required database modules and available environment variables for database
connection customisation
* Normalises the DATABASE_PASSWORD tests environment variable to match
the name in Django's database settings object
Fix doc and test on ES6 python client compat
This commit changes the statement that version < 6.3.1 of the
elasticsearch python client should be used to instead state
that 6.4.0 is fine.
It also update the tests to reflect the statement.
Initially the `update_all_types` argument has been used to work
around an issue described in:
https://github.com/wagtail/wagtail/issues/2968
This argument was removed in elasticsearch-py 6.3.1 and making
use of it was raising an error.
With 6.4.0 nothing is raising anymore.
