update pep484 tests

staticmethod can now be type-qualified, so static checkers
are complaining.  however we don't want to do that here
because it's going to fail in Python 3.7.   just use
an ignore type for the one place we do this right now.

Add pep484 tox target as we are getting jenkins to
target this for all projects.

Change-Id: Ic4db0fc7dd0bfe01308027c911f4dcb288bb169e

Author: zzzeek

dogpile/cache/api.py

@@ -152,15 +152,15 @@ class CacheBackend:
 
     """
 
-    serializer: Union[None, Serializer, staticmethod] = None
+    serializer: Union[None, Serializer] = None
     """Serializer function that will be used by default if not overridden
     by the region.
 
     .. versionadded:: 1.1
 
     """
 
-    deserializer: Union[None, Deserializer, staticmethod] = None
+    deserializer: Union[None, Deserializer] = None
     """deserializer function that will be used by default if not overridden
     by the region.
 
@@ -446,10 +446,10 @@ def delete_multi(
 
 
 class DefaultSerialization:
-    serializer: Union[None, Serializer, staticmethod] = staticmethod(
+    serializer: Union[None, Serializer] = staticmethod(  # type: ignore
         pickle.dumps
     )
-    deserializer: Union[None, Deserializer, staticmethod] = staticmethod(
+    deserializer: Union[None, Deserializer] = staticmethod(  # type: ignore
         pickle.loads
     )
 

tox.ini

@@ -51,7 +51,8 @@ commands=
 sitepackages=False
 usedevelop=True
 
-[testenv:mypy]
+
+[testenv:pep484]
 basepython = python3
 deps=
     mypy
@@ -64,6 +65,13 @@ deps=
     types-decorator
 commands = mypy ./dogpile/
 
+[testenv:mypy]
+basepython = python3
+deps=
+    {[testenv:pep484]deps}
+commands = mypy ./dogpile/
+
+
 # thanks to https://julien.danjou.info/the-best-flake8-extensions/
 [testenv:pep8]
 basepython = python3