tests: Enable SQLAlchemy 2.0 deprecation warnings

Well, sort of. We enable them but immediately filter out the ones we're
actually seeing, the rationale being that we can address these in a
piecemeal fashion without the risk of introducing new issues.

There's a lot more to be done here. However, the work done in oslo.db
and other projects [1] should provide a guide for how to resolve the
outstanding issues.

[1] https://review.opendev.org/q/topic:%2522sqlalchemy-20%2522

Change-Id: Id4c5e80d665fa90d07517bc58c26b44d543d34b3
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

keystone/tests/unit/ksfixtures/warnings.py

@@ -31,8 +31,8 @@ class WarningsFixture(fixtures.Fixture):
 
         warnings.filterwarnings(
             'error',
+            module='keystone',
             category=DeprecationWarning,
-            module='^keystone\\.',
         )
 
         warnings.filterwarnings(
@@ -59,19 +59,70 @@ class WarningsFixture(fixtures.Fixture):
             message=r"Using function/method 'db_version\(\)' is deprecated",
         )
 
-        # TODO(stephenfin): Remove these when we drop support for
-        # sqlalchemy-migrate
+        warnings.filterwarnings(
+            'error',
+            module='keystone',
+            category=sqla_exc.SAWarning,
+        )
+
         warnings.filterwarnings(
             'ignore',
             category=sqla_exc.SADeprecationWarning,
-            module='migrate.versioning',
         )
 
-        # TODO(stephenfin): We should filter on the specific RemovedIn20Warning
-        # warnings that affect us, so that we can slowly start addressing them
-        warnings.simplefilter('error', sqla_exc.SAWarning)
-        if hasattr(sqla_exc, 'RemovedIn20Warning'):
-            warnings.simplefilter('ignore', sqla_exc.RemovedIn20Warning)
+        # Enable deprecation warnings for keystone itself to capture upcoming
+        # SQLALchemy changes
+
+        warnings.filterwarnings(
+            'error',
+            module='keystone',
+            category=sqla_exc.SADeprecationWarning,
+        )
+
+        # ...but filter everything out until we get around to fixing them
+        # TODO(stephenfin): Fix all of these
+
+        warnings.filterwarnings(
+            'ignore',
+            module='keystone',
+            message=r'Passing a string to Connection.execute\(\) is .*',
+            category=sqla_exc.SADeprecationWarning,
+        )
+
+        warnings.filterwarnings(
+            'ignore',
+            module='keystone',
+            message=r'The Query.get\(\) method is considered legacy .*',
+            category=sqla_exc.SADeprecationWarning,
+        )
+
+        warnings.filterwarnings(
+            'ignore',
+            module='keystone',
+            message=r'The autoload parameter is deprecated .*',
+            category=sqla_exc.SADeprecationWarning,
+        )
+
+        warnings.filterwarnings(
+            'ignore',
+            module='keystone',
+            message=r'The legacy calling style of select\(\) .*',
+            category=sqla_exc.SADeprecationWarning,
+        )
+
+        warnings.filterwarnings(
+            'ignore',
+            module='keystone',
+            message=r'The MetaData.bind argument is deprecated .*',
+            category=sqla_exc.SADeprecationWarning,
+        )
+
+        warnings.filterwarnings(
+            'ignore',
+            module='keystone',
+            message=r'".*" object is being merged into a Session along .*',
+            category=sqla_exc.SADeprecationWarning,
+        )
 
         self.addCleanup(self._reset_warning_filters)
 

tox.ini

@@ -8,6 +8,8 @@ basepython = python3
 usedevelop = True
 setenv =
   PYTHONDONTWRITEBYTECODE=1
+# TODO(stephenfin): Remove once we bump our upper-constraint to SQLAlchemy 2.0
+  SQLALCHEMY_WARN_20=1
 deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/test-requirements.txt