improve test

Author: d-w-moore

irods/test/data_obj_test.py

@@ -55,7 +55,7 @@ def is_localhost_synonym(name):
 from irods.test.helpers import iRODSUserLogins
 import irods.exception as ex
 from irods.column import Criterion
-from irods.data_object import chunks, irods_dirname
+from irods.data_object import chunks, irods_dirname, _REPLICA_FITNESS_SORT_KEY_FN
 import irods.test.helpers as helpers
 import irods.test.modules as test_modules
 import irods.keywords as kw
@@ -2989,7 +2989,6 @@ def test_handling_of_termination_signals_during_multithread_put__issue_722(self)
 
         test_put__issue_722(self)
 
-    @unittest.skipIf(irods.version.version_as_tuple() < (4,), 'too soon for this test.')
     def test_modified_default_sorting_of_replicas__issue_647(self):
         basename = unique_name(my_function_name(), datetime.now()) + '_dataobj_647'
         with self.create_simple_resc() as newResc1, self.create_simple_resc() as newResc2:
@@ -3005,13 +3004,27 @@ def test_modified_default_sorting_of_replicas__issue_647(self):
                     f.write(b'.')
                 time.sleep(2)
 
-                # Voting should ensure exactly two good replicas of the three.
                 data.replicate(resource=newResc2)
 
-                # refresh replicas
-                data = self.sess.data_objects.get(data.path)
+                # At this point, there should ensure exactly two good replicas of the three.
+                # Assert exactly one replica is stale, to corroborate 
+                data = self.sess.data_objects.get(
+                    data.path, 
+                    replica_sort_function=lambda row: int(row[DataObject.replica_status])
+                )
+                self.assertEqual(
+                    [repl.status for repl in data.replicas],
+                    ['0', '1', '1']
+                )
+
+                options = {}
+                if irods.version.version_as_tuple() < (4,):
+                    options['replica_sort_function'] = _REPLICA_FITNESS_SORT_KEY_FN
+
+                # Get a data object with the PRC3-alternative/PRC4-default sort order.
+                data = self.sess.data_objects.get(data.path, **options)
 
-                # Test replica sorting.
+                # Test default replica sorting.
                 self.assertEqual(data.replicas[0].status, '1')
                 self.assertEqual(data.replicas[0].modify_time, data.modify_time)
                 self.assertGreater(data.replicas[0].modify_time, data.replicas[1].modify_time)