LP #281156: 'AccessControl.SecurityInfo.secureModule' dropped ModuleS…

…ecurity

for failed imports, obscuring later attempts to import the same broken module.

'AccessControl.ZopeGuards.guarded_import' mapped some Unauthorized exceptions
onto ImportErrors:  don't do that!  Also, removed mutable defaults from
argument list, improved tests.

tests/testPythonScript.py

@@ -231,8 +231,9 @@ def testSubversiveExcept(self):
         self.assertPSRaises(SyntaxError, path='subversive_except')
 
     def testBadImports(self):
-        self.assertPSRaises(ImportError, body="from string import *")
-        self.assertPSRaises(ImportError, body="import mmap")
+        from zExceptions import Unauthorized
+        self.assertPSRaises(Unauthorized, body="from string import *")
+        self.assertPSRaises(Unauthorized, body="import mmap")
 
     def testAttributeAssignment(self):
         # It's illegal to assign to attributes of anything that