Special thanks to Hannes Ljungberg for finding multiple implementation
gaps.
Thanks also to Simon Charette, Adam Johnson, and Mariusz Felisiak for
reviews.
Thanks Jared Chung, Tom Carrick, David Smith, Nick Pope, and Mariusz
Felisiak for reviews.
Co-authored-by: Mariusz Felisiak <felisiak.mariusz@gmail.com>
Co-authored-by: Nick Pope <nick@nickpope.me.uk>
- Used selected "databases" instead of django.db.connections.
- Made routers in tests.migrations skip migrations on unexpected
databases.
- Added DiscoverRunnerGetDatabasesTests.assertSkippedDatabases() hook
which properly asserts messages about skipped databases.
* assertIsNone()/assertIsNotNone() instead of comparing to None.
* assertLess() for < comparisons.
* assertIs() for 'is' expressions.
* assertIsInstance() for isinstance() expressions.
* rounding of assertAlmostEqual() for round() expressions.
* assertIs(..., True/False) instead of comparing to True/False.
* assertIs()/assertIsNot() for ==/!= comparisons.
* assertNotEqual() for == comparisons.
* assertTrue()/assertFalse() instead of comparing to True/False.
This is preferrable to writing in the current working directory because
it eliminates the risk to leak unwanted files, which can result in very
weird test failures.
Also this will help if we ever try to run these tests concurrently.
This commit touchs various parts of the code base and test framework. Any
found usage of opening a cursor for the sake of initializing a connection
has been replaced with 'ensure_connection()'.
