OFS ObjectManager: Fixed list_imports() to tolerate missing

import directories. (Merged from trunk.)

doc/CHANGES.txt

@@ -27,6 +27,9 @@ Zope Changes
 
     Bugs fixed
 
+     - OFS ObjectManager: Fixed list_imports() to tolerate missing
+       import directories.
+
      - Collector #1965: 'get_transaction' missing from builtins without
        sufficient deprecation notice (ZODB 3.6 properly removed it, but
        Zope needs to keep it for another release).

lib/python/OFS/ObjectManager.py

@@ -619,6 +619,8 @@ class ObjectManager(
             paths.append(cfg.instancehome)
         for impath in paths:
             directory = os.path.join(impath, 'import')
+            if not os.path.isdir(directory):
+                continue
             listing += [f for f in os.listdir(directory)
                         if f.endswith('.zexp') or f.endswith('.xml')]
         return listing

lib/python/OFS/tests/testObjectManager.py

@@ -108,7 +108,6 @@ class ObjectManagerTests(PlacelessSetup, unittest.TestCase):
         self.assertEqual( si.__ac_local_roles__, None )
 
     def test_setObject_set_owner_with_emergency_user( self ):
-
         om = self._makeOne()
 
         newSecurityManager( None, emergency_user )
@@ -380,6 +379,16 @@ class ObjectManagerTests(PlacelessSetup, unittest.TestCase):
         self.assertRaises(BadRequest, om._setObject, 'REQUEST', si)
         self.assertRaises(BadRequest, om._setObject, '/', si)
 
+    def test_list_imports(self):
+        om = self._makeOne()
+        # This must work whether we've done "make instance" or not.
+        # So list_imports() may return an empty list, or whatever's
+        # in skel/import. Tolerate both cases.
+        self.failUnless(isinstance(om.list_imports(), list))
+        for filename in om.list_imports():
+            self.failUnless(filename.endswith('.zexp') or
+                            filename.endswith('.xml'))
+
 def test_suite():
     suite = unittest.TestSuite()
     suite.addTest( unittest.makeSuite( ObjectManagerTests ) )