Don't raise on pytest deprecation warnings

py.test 5.4.0 emits deprecation warnings for pytest.Class.
make sure we don't raise for these, and log the code that will
be used for 5.4.0 when we bump requirements.

Fixes: #668
Change-Id: I83e0402c4a6b2365a63b58d052c6989df3a37328

2 files changed, 25 insertions, 0 deletions

diff --git a/alembic/testing/plugin/plugin_base.py b/alembic/testing/plugin/plugin_base.py
index 9535282..276bc56 100644
--- a/alembic/testing/plugin/plugin_base.py
+++ b/alembic/testing/plugin/plugin_base.py
@@ -11,10 +11,12 @@ import sys
 
 from sqlalchemy.testing.plugin.plugin_base import *  # noqa
 from sqlalchemy.testing.plugin.plugin_base import post
+from sqlalchemy.testing.plugin.plugin_base import post_begin as sqla_post_begin
 from sqlalchemy.testing.plugin.plugin_base import stop_test_class as sqla_stc
 
 py3k = sys.version_info >= (3, 0)
 
+
 if py3k:
 
     ABC = abc.ABC
@@ -24,6 +26,21 @@ else:
         __metaclass__ = abc.ABCMeta
 
 
+def post_begin():
+    sqla_post_begin()
+
+    import warnings
+
+    try:
+        import pytest
+    except ImportError:
+        pass
+    else:
+        warnings.filterwarnings(
+            "once", category=pytest.PytestDeprecationWarning
+        )
+
+
 # override selected SQLAlchemy pytest hooks with vendored functionality
 def stop_test_class(cls):
     sqla_stc(cls)
diff --git a/alembic/testing/plugin/pytestplugin.py b/alembic/testing/plugin/pytestplugin.py
index d6efdf4..1c8be05 100644
--- a/alembic/testing/plugin/pytestplugin.py
+++ b/alembic/testing/plugin/pytestplugin.py
@@ -33,6 +33,14 @@ def pytest_configure(config):
 def pytest_pycollect_makeitem(collector, name, obj):
 
     if inspect.isclass(obj) and plugin_base.want_class(name, obj):
+
+        # in pytest 5.4.0
+        # return [
+        #     pytest.Class.from_parent(collector,
+        # name=parametrize_cls.__name__)
+        #     for parametrize_cls in _parametrize_cls(collector.module, obj)
+        # ]
+
         return [
             pytest.Class(parametrize_cls.__name__, parent=collector)
             for parametrize_cls in _parametrize_cls(collector.module, obj)