100% coverage for test_checker.py

- Modern assert methods
- Whitespace cleanup
- A whole test class was being skipped because of a duplicate name.

src/zope/security/checker.py

@@ -633,7 +633,7 @@ def moduleChecker(module):
                             '__eq__', '__ne__', '__lt__', '__gt__',
                             '__le__', '__ge__'])
 
-class BasicTypes(dict):
+class _BasicTypes(dict):
     """Basic Types Dictionary
 
     Make sure that checkers are really updated, when a new type is added.
@@ -685,7 +685,7 @@ def update(self, d):
 else: # pragma: no cover
     _basic_types[type(pytz.UTC)] = NoProxy
 
-BasicTypes = BasicTypes(_basic_types)
+BasicTypes = _BasicTypes(_basic_types)
 del _basic_types
 
 # Available for tests. Located here so it can be kept in sync with BasicTypes.