id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
16969	Avoid selecting production database prior to test database setup/teardown	Andreas Pelme	nobody	"I am playing around with running my test suite with pytest and pytest-xdist. I would like to be able to run my tests in parallell, which would probably be a massive speedup on a decent multi-core CPU. To isolate tests properly, I am dynamically modifying the database name in the settings, to create a separate test database for each process.

However, when the test database is created, Django creates a cursor to the production database before setting up/destroying the test database. Since I am generating the database name dynamically in each process, this causes problems for me, since I do not know the name and can create it beforehand. I see no reason for doing this, so I would like to skip selecting the production database before creating/destroying the test database.

The behavior is when creating a cursor without specifying a database varies a bit across the backends:

 * sqlite - this is not a problem
 * mysql - it is possible to omit the database name
 * postgesql - a database name must be given, but rather than choosing the production name, the default ""postgesql"" database can be used
 * oracle - I am unable to test this since I do not have an Oracle database available

I have modified django/db/backends/creation.py to set connection.settings_dict['NAME'] to None instead of the production database name during creation/destroy. I also made a small change in the postgres backend to use the ""postgesql"" database if None is supplied.

I have run the Django test suite for sqlite, mysql and postgesql and this does not seems to cause any problems."	Cleanup/optimization	closed	Testing framework	dev	Normal	fixed			Ready for checkin	1	0	0	0	0	0