=== modified file 'bzrlib/tests/per_repository/test_repository.py'
--- bzrlib/tests/per_repository/test_repository.py	2010-05-06 23:41:35 +0000
+++ bzrlib/tests/per_repository/test_repository.py	2012-11-03 22:12:11 +0000
@@ -744,6 +744,14 @@
         self.assertEqual(['C'], list(kg.heads(['A', 'B', 'C'])))
         self.assertEqual(['A', 'B', 'C'], list(kg.topo_sort()))
 
+    def test_get_known_graph_ancestry_lock(self):
+        repo = self.make_repository('repo')
+        repo.lock_write()
+        self.addCleanup(repo.unlock)
+        repo.start_write_group()
+        self.addCleanup(repo.abort_write_group)
+        repo.get_known_graph_ancestry([None])
+
     def test_parent_map_type(self):
         tree = self.make_branch_and_tree('here')
         tree.lock_write()