[WIPTEST] Types fixes

cfme/infrastructure/datastore.py

@@ -18,6 +18,7 @@
 from cfme.exceptions import displayed_not_implemented
 from cfme.exceptions import ItemNotFound
 from cfme.exceptions import MenuItemNotFound
+from cfme.infrastructure.provider import InfraProvider
 from cfme.modeling.base import BaseCollection
 from cfme.modeling.base import BaseEntity
 from cfme.optimize.utilization import DatastoreUtilizationTrendsView
@@ -216,7 +217,7 @@ class Datastore(Pretty, BaseEntity, Taggable, CustomButtonEventsMixin):
     pretty_attrs = ['name', 'provider_key']
     _param_name = ParamClassName('name')
     name = attr.ib()
-    provider = attr.ib()
+    provider: InfraProvider = attr.ib()
     type = attr.ib(default=None)
 
     def __attrs_post_init__(self):
@@ -358,7 +359,7 @@ def wait_candu_data_available(self, timeout=900):
 
 
 @attr.s
-class DatastoreCollection(BaseCollection):
+class DatastoreCollection(BaseCollection[Datastore]):
     """Collection class for :py:class:`cfme.infrastructure.datastore.Datastore`"""
     ENTITY = Datastore
 
@@ -421,7 +422,6 @@ def run_smartstate_analysis(self, *datastores):
         datastores = list(datastores)
 
         checked_datastores = list()
-
         view = navigate_to(self, 'All')
 
         for datastore in datastores:
@@ -469,6 +469,7 @@ class DetailsFromProvider(CFMENavigateStep):
     VIEW = DatastoreDetailsView
 
     def prerequisite(self):
+        # TODO use DatastoresOfProvider
         prov_view = navigate_to(self.obj.provider, 'Details')
         prov_view.entities.summary('Relationships').click_at('Datastores')
         return self.obj.create_view(DatastoresView)

cfme/modeling/base.py

@@ -1,4 +1,7 @@
 from collections.abc import Callable
+from typing import Generic
+from typing import Type
+from typing import TypeVar
 
 import attr
 from cached_property import cached_property
@@ -87,8 +90,11 @@ def __getattr__(self, name):
         return self._collection_cache[name]
 
 
+T = TypeVar('T')
+
+
 @attr.s
-class BaseCollection(NavigatableMixin):
+class BaseCollection(NavigatableMixin, Generic[T]):
     """Class for helping create consistent Collections
 
     The BaseCollection class is responsible for ensuring two things:
@@ -99,8 +105,7 @@ class BaseCollection(NavigatableMixin):
     This class works in tandem with the entrypoint loader which ensures that the correct
     argument names have been used.
     """
-
-    ENTITY = None
+    ENTITY: Type[T]
 
     parent = attr.ib(repr=False)
     filters = attr.ib(default=attr.Factory(dict))
@@ -120,13 +125,13 @@ def for_appliance(cls, appliance, *k, **kw):
     def for_entity(cls, obj, *k, **kw):
         return cls(obj, *k, **kw)
 
+    def instantiate(self, *args, **kwargs) -> T:
+        return self.ENTITY.from_collection(self, *args, **kwargs)
+
     @classmethod
     def for_entity_with_filter(cls, obj, filt, *k, **kw):
         return cls.for_entity(obj, *k, **kw).filter(filt)
 
-    def instantiate(self, *args, **kwargs):
-        return self.ENTITY.from_collection(self, *args, **kwargs)
-
     def filter(self, filter):
         filters = self.filters.copy()
         filters.update(filter)
@@ -146,7 +151,7 @@ class BaseEntity(NavigatableMixin):
     argument names have been used.
     """
 
-    parent = attr.ib(repr=False)  # This is the collection or not
+    parent: BaseCollection = attr.ib(repr=False)  # This is the collection or not
 
     # TODO This needs removing as we need proper __eq__ on objects, but it is part of a
     #      much larger discussion
@@ -157,7 +162,7 @@ def appliance(self):
         return self.parent.appliance
 
     @classmethod
-    def from_collection(cls, collection, *k, **kw):
+    def from_collection(cls, collection: BaseCollection, *k, **kw):
         return cls(collection, *k, **kw)
 
     @cached_property