diff --git a/tests/test-py3-commands.t b/tests/test-py3-commands.t
--- a/tests/test-py3-commands.t
+++ b/tests/test-py3-commands.t
@@ -237,3 +237,79 @@
   $ $PYTHON3 $HGBIN bookmark book
   $ $PYTHON3 $HGBIN bookmarks
    * book                      0:71c96e924262
+
+`hg merge` without any conflicts work
+
+  $ echo foo > bar
+  $ $PYHTON3 $HGBIN status
+  ? bar
+  $ $PYTHON3 $HGBIN commit -Aqm "added bar with foo"
+  $ $PYTHON3 $HGBIN log -G
+  @  changeset:   2:936056149ac7
+  |  bookmark:    book
+  |  tag:         tip
+  |  parent:      0:71c96e924262
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     added bar with foo
+  |
+  | o  changeset:   1:e1e9167203d4
+  |/   user:        test
+  |    date:        Thu Jan 01 00:00:00 1970 +0000
+  |    summary:     message
+  |
+  o  changeset:   0:71c96e924262
+     user:        test
+     date:        Thu Jan 01 00:00:00 1970 +0000
+     summary:     commit performed in Python 3
+  
+  $ $PYTHON3 $HGBIN merge -r 1
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+  $ $PYTHON3 $HGBIN log -G
+  @  changeset:   2:936056149ac7
+  |  bookmark:    book
+  |  tag:         tip
+  |  parent:      0:71c96e924262
+  |  user:        test
+  |  date:        Thu Jan 01 00:00:00 1970 +0000
+  |  summary:     added bar with foo
+  |
+  | @  changeset:   1:e1e9167203d4
+  |/   user:        test
+  |    date:        Thu Jan 01 00:00:00 1970 +0000
+  |    summary:     message
+  |
+  o  changeset:   0:71c96e924262
+     user:        test
+     date:        Thu Jan 01 00:00:00 1970 +0000
+     summary:     commit performed in Python 3
+  
+  $ $PYTHON3 $HGBIN commit -m "merge commit in python 3"
+
+  $ $PYTHON3 $HGBIN log -G
+  @    changeset:   3:523f17ef84ba
+  |\   bookmark:    book
+  | |  tag:         tip
+  | |  parent:      2:936056149ac7
+  | |  parent:      1:e1e9167203d4
+  | |  user:        test
+  | |  date:        Thu Jan 01 00:00:00 1970 +0000
+  | |  summary:     merge commit in python 3
+  | |
+  | o  changeset:   2:936056149ac7
+  | |  parent:      0:71c96e924262
+  | |  user:        test
+  | |  date:        Thu Jan 01 00:00:00 1970 +0000
+  | |  summary:     added bar with foo
+  | |
+  o |  changeset:   1:e1e9167203d4
+  |/   user:        test
+  |    date:        Thu Jan 01 00:00:00 1970 +0000
+  |    summary:     message
+  |
+  o  changeset:   0:71c96e924262
+     user:        test
+     date:        Thu Jan 01 00:00:00 1970 +0000
+     summary:     commit performed in Python 3
+