diff --git a/tests/test-ancestor.py b/tests/test-ancestor.py
--- a/tests/test-ancestor.py
+++ b/tests/test-ancestor.py
@@ -220,9 +220,9 @@ def test_lazyancestors():
 # DAGs that have been known to be problematic, and, optionally, known pairs
 # of revisions and their expected ancestor list.
 dagtests = [
-    ('+2*2*2/*3/2', {}),
-    ('+3*3/*2*2/*4*4/*4/2*4/2*2', {}),
-    ('+2*2*/2*4*/4*/3*2/4', {(6, 7): [3, 5]}),
+    (b'+2*2*2/*3/2', {}),
+    (b'+3*3/*2*2/*4*4/*4/2*4/2*2', {}),
+    (b'+2*2*/2*4*/4*/3*2/4', {(6, 7): [3, 5]}),
 ]
 def test_gca():
     u = uimod.ui.load()