Get test suite to full pass with SQLAlchemy 2.0

Remaining issues encountered when running with SQLAlchemy 2.0 for real:

* Never call str() on a URL and expect it to be meaningful anymore.
  The password is aggressively obfuscated now (users absolultely
  wouldn't let us leave it as is)
* More utilities and fixtures that were calling begin() within a
  block that would have already begun
* isnot is now called is_not; mocking "isnot" leads into too many
  weird compat layers
* ORM InstrumentedAttribute and internals use __slots__ now, mock
  seems to not be able to patch methods.  Ideally these tests would use
  a comparator subclass or something
* Connection.connection.connection is now called driver_connection,
  SQLAlchemy keeps the old name available however oslo.db test suite
  does not appear to tolerate the deprecation warning emitted,
  so add a compat layer
* mapper() is fully removed from 2.0, not sure if there is another
  not-yet-committed gerrit that removes mapper()

[1] https://docs.sqlalchemy.org/en/20/core/engines.html#sqlalchemy.create_engine.params.pool_pre_ping
[2] https://docs.sqlalchemy.org/en/20/changelog/changelog_20.html#change-2fe37eaf2295cebd3bb4ee8e5b8c575c
[3] https://github.com/sqlalchemy/sqlalchemy/issues/5648

Change-Id: Ifaca67c07f008d8bc0febeecd3e200cc7ee7a4b0

1 files changed, 11 insertions, 0 deletions

diff --git a/releasenotes/notes/sqlalchemy-20-0a193a01c70f805a.yaml b/releasenotes/notes/sqlalchemy-20-0a193a01c70f805a.yaml
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index 0000000..b2c8d62
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+---
+features:
+  - |
+    oslo.db now supports SQLAlchemy 2.0.
+  - |
+    A new ``oslo_db.compat`` module has been added. This provides a number of
+    shims for handling differences between SQLAlchemy 1.x and 2.x.
+upgrade:
+  - |
+    The ability to create engine facades that used autocommit, first deprecated
+    in 12.1.0, has now been removed. This is not supported in SQLAlchemy 2.x.