diff --git a/contrib/python3-whitelist b/contrib/python3-whitelist
--- a/contrib/python3-whitelist
+++ b/contrib/python3-whitelist
@@ -217,6 +217,7 @@
 test-merge-revert2.t
 test-merge-subrepos.t
 test-merge-symlinks.t
+test-merge-tools.t
 test-merge-types.t
 test-merge1.t
 test-merge10.t
diff --git a/tests/test-merge-tools.t b/tests/test-merge-tools.t
--- a/tests/test-merge-tools.t
+++ b/tests/test-merge-tools.t
@@ -1558,7 +1558,7 @@
   $ hg update -q -C 2
   $ hg merge -y -r tip --tool echo --config merge-tools.echo.args='$base $local $other $output'
   merging f and f.txt to f.txt
-  */f~base.?????? $TESTTMP/f.txt.orig */f~other.??????.txt $TESTTMP/f.txt (glob)
+  */f~base.* $TESTTMP/f.txt.orig */f~other.*.txt $TESTTMP/f.txt (glob)
   0 files updated, 1 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)