Add DeclarativeMeta to globals

Fixed issue in mypy plugin where newly added support for
:func:`_orm.as_declarative` needed to more fully add the
``DeclarativeMeta`` class to the mypy interpreter's state so that it does
not result in a name not found error; additionally improves how global
names are setup for the plugin including the ``Mapped`` name.

Introduces directory oriented testing as well, where a full
set of files will be copied, mypy runs, then zero or more patches
are applied and mypy is run again, to fully test incremental
behaviors.

Fixes: sqlalchemy/sqlalchemy2-stubs/#14
Change-Id: Ide785c07e19ba0694e8cf6f91560094ecb182016

1 files changed, 1 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 783140502..6eea65c8f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -130,6 +130,7 @@ deps=
      mock; python_version < '3.3'
      importlib_metadata; python_version < '3.8'
      mypy
+     patch==1.*
      git+https://github.com/sqlalchemy/sqlalchemy2-stubs
 commands =
     pytest test/ext/mypy/test_mypy_plugin_py3k.py {posargs}