Refs #25899 -- Improved visibility of TEST database settings in testing docs.

database between runs. If the database does not exist, it will first be

created. Any migrations will also be applied in order to keep it p to date.

By default the test databases get their names by prepending ``test_``

to the value of the :setting:`NAME` settings for the databases

defined in :setting:`DATABASES`. When using the SQLite database engine

the tests will by default use an in-memory database (i.e., the

database will be created in memory, bypassing the filesystem

entirely!). If you want to use a different database name, specify

:setting:`NAME <TEST_NAME>` in the :setting:`TEST <DATABASE-TEST>`

dictionary for any given database in :setting:`DATABASES`.

The default test database names are created by prepending ``test_`` to the

value of each :setting:`NAME` in :setting:`DATABASES`. When using SQLite, the

tests will use an in-memory database by default (i.e., the database will be

created in memory, bypassing the filesystem entirely!). The :setting:`TEST

<DATABASE-TEST>` dictionary in :setting:`DATABASES` offers a number of settings

to configure your test database. For example, if you want to use a different

database name, specify :setting:`NAME <TEST_NAME>` in the :setting:`TEST

<DATABASE-TEST>` dictionary for any given database in :setting:`DATABASES`.

On PostgreSQL, :setting:`USER` will also need read access to the built-in

``postgres`` database.