Support pytest 6.x

pytest has removed support for pytest.Class(..parent)
and we need to use from_parent.

Also works around new issue for 6.1.0

References: pytest-dev/pytest#7807

Change-Id: Ia5fed9b22e76c99f71489283acee207f996f52a4

alembic/__init__.py

@@ -5,7 +5,7 @@
 from .runtime import environment
 from .runtime import migration
 
-__version__ = '1.4.4'
+__version__ = "1.4.4"
 
 sys.modules["alembic.migration"] = migration
 sys.modules["alembic.environment"] = environment

alembic/testing/plugin/pytestplugin.py

@@ -33,16 +33,10 @@ 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)
-        # ]
+        ctor = getattr(pytest.Class, "from_parent", pytest.Class)
 
         return [
-            pytest.Class(parametrize_cls.__name__, parent=collector)
+            ctor(name=parametrize_cls.__name__, parent=collector)
             for parametrize_cls in _parametrize_cls(collector.module, obj)
         ]
     elif (

tox.ini

@@ -7,7 +7,7 @@ SQLA_REPO = {env:SQLA_REPO:git+https://github.com/sqlalchemy/sqlalchemy.git}
 [testenv]
 cov_args=--cov=alembic --cov-report term --cov-report xml
 
-deps=pytest!=3.9.1,!=3.9.2
+deps=pytest>4.6
      pytest-xdist
      mock
      sqla11: {[tox]SQLA_REPO}@rel_1_1
@@ -30,7 +30,7 @@ usedevelop=
 # only use --dropfirst option if we're *not* using -n;
 # if -n is used, we're working in brand new DBs anyway
 setenv=
-    BASECOMMAND=python -m pytest
+    BASECOMMAND=python -m pytest --rootdir {toxinidir}
     WORKERS=-n4
     sqla079: WORKERS=--dropfirst
     cov: COVERAGE={[testenv]cov_args}