diff --git a/tests/run-tests.py b/tests/run-tests.py
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -346,8 +346,9 @@ DAEMON_PIDS = os.environ["DAEMON_PIDS"] 
 HGRCPATH = os.environ["HGRCPATH"] = os.path.join(HGTMP, '.hgrc')
 
 os.environ["HGEDITOR"] = sys.executable + ' -c "import sys; sys.exit(0)"'
-os.environ["HGMERGE"]  = 'python "%s"' % os.path.join(TESTDIR, os.path.pardir,
-                                                      'contrib', 'simplemerge')
+os.environ["HGMERGE"]  = ('python "%s" -L my -L other'
+                          % os.path.join(TESTDIR, os.path.pardir, 'contrib',
+                                         'simplemerge'))
 os.environ["HGUSER"]   = "test"
 os.environ["HGENCODING"] = "ascii"
 os.environ["HGENCODINGMODE"] = "strict"
diff --git a/tests/test-conflict b/tests/test-conflict
--- a/tests/test-conflict
+++ b/tests/test-conflict
@@ -11,5 +11,5 @@ echo "something else" > a
 hg commit -m branch2 -d "1000000 0"
 hg merge 1
 hg id
-egrep -v ">>>|<<<" a
+cat a
 hg status
diff --git a/tests/test-conflict.out b/tests/test-conflict.out
--- a/tests/test-conflict.out
+++ b/tests/test-conflict.out
@@ -7,7 +7,9 @@ There are unresolved merges, you can red
   hg update -C 2
   hg merge 1
 e7fe8eb3e180+0d24b7662d3e+ tip
+<<<<<<< my
 something else
 =======
 something
+>>>>>>> other
 M a
diff --git a/tests/test-merge-revert2 b/tests/test-merge-revert2
--- a/tests/test-merge-revert2
+++ b/tests/test-merge-revert2
@@ -27,7 +27,7 @@ hg id
 hg update -C 0
 echo "changed file1 different" >> file1
 hg update
-hg diff --nodates | sed -e "s/\(<<<<<<<\) .*/\1/" -e "s/\(>>>>>>>\) .*/\1/"
+hg diff --nodates
 hg status
 hg id
 hg revert --no-backup --all
diff --git a/tests/test-merge-revert2.out b/tests/test-merge-revert2.out
--- a/tests/test-merge-revert2.out
+++ b/tests/test-merge-revert2.out
@@ -23,11 +23,11 @@ diff -r f248da0d4c3e file1
 @@ -1,3 +1,7 @@ added file1
  added file1
  another line of text
-+<<<<<<<
++<<<<<<< my
 +changed file1 different
 +=======
  changed file1
-+>>>>>>>
++>>>>>>> other
 M file1
 f248da0d4c3e+ tip
 reverting file1
diff --git a/tests/test-merge7 b/tests/test-merge7
--- a/tests/test-merge7
+++ b/tests/test-merge7
@@ -59,7 +59,7 @@ cd ../test-b
 hg pull ../test-a
 hg merge --debug
 
-cat test.txt | sed "s% .*%%"
+cat test.txt
 
 hg debugindex .hg/store/data/test.txt.i
 
diff --git a/tests/test-merge7.out b/tests/test-merge7.out
--- a/tests/test-merge7.out
+++ b/tests/test-merge7.out
@@ -33,11 +33,11 @@ There are unresolved merges, you can red
   hg update -C 3
   hg merge 4
 one
-<<<<<<<
+<<<<<<< my
 two-point-five
 =======
 two-point-one
->>>>>>>
+>>>>>>> other
 three
    rev    offset  length   base linkrev nodeid       p1           p2
      0         0       7      0       0 01365c4cca56 000000000000 000000000000