tests: Enable SADeprecationWarning warnings

Highlight use of deprecated SQLAlchemy APIs to ensure we keep on top of
things. This requires resolving the following SADeprecationWarning
warnings:

  The from_engine() method on Inspector is deprecated and will be
  removed in a future release.  Please use the sqlalchemy.inspect()
  function on an Engine or Connection in order to acquire an Inspector.

  The Column.copy() method is deprecated and will be removed in a future
  release.

  The ColumnCollectionConstraint.copy() method is deprecated and will be
  removed in a future release.

There are more warnings to be resolved related to SQLAlchemy 2.0, but
those require a special environment option (SQLALCHEMY_WARN_20) to
trigger and a lot of work to resolve. We'll address those in a series of
follow-ups.

Change-Id: I34b395e6d50f4e4151178c327d94308e6f5d5b6e
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/oslo_db/tests/fixtures.py b/oslo_db/tests/fixtures.py
new file mode 100644
index 0000000..c08a34d
--- /dev/null
+++ b/oslo_db/tests/fixtures.py
@@ -0,0 +1,36 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import warnings
+
+import fixtures
+from sqlalchemy import exc as sqla_exc
+
+
+class WarningsFixture(fixtures.Fixture):
+    """Filters out warnings during test runs."""
+
+    def setUp(self):
+        super().setUp()
+        # Make deprecation warnings only happen once to avoid spamming
+        warnings.simplefilter('once', DeprecationWarning)
+
+        warnings.filterwarnings(
+            'error', message='Evaluating non-mapped column expression',
+            category=sqla_exc.SAWarning)
+
+        # Enable deprecation warnings to capture upcoming SQLAlchemy changes
+        warnings.filterwarnings(
+            'error',
+            category=sqla_exc.SADeprecationWarning)
+
+        self.addCleanup(warnings.resetwarnings)