Add diff3 conflictstyle support for git merge conflicts.
diff --git a/tests/check_merge_conflict_test.py b/tests/check_merge_conflict_test.py
index 3d719bd..07805b1 100644
--- a/tests/check_merge_conflict_test.py
+++ b/tests/check_merge_conflict_test.py
@@ -37,12 +37,21 @@
         cmd_output('git', 'commit', '-am', 'clone commit2')
         cmd_output('git', 'pull', retcode=None)
         # We should end up in a merge conflict!
-        assert io.open('f1').read().startswith(
+        f1 = io.open('f1').read()
+        assert f1.startswith(
             '<<<<<<< HEAD\n'
             'child\n'
             '=======\n'
             'parent\n'
             '>>>>>>>'
+        ) or f1.startswith(
+            '<<<<<<< HEAD\n'
+            'child\n'
+            # diff3 conflict style git merges add this line:
+            '||||||| merged common ancestors\n'
+            '=======\n'
+            'parent\n'
+            '>>>>>>>'
         )
         assert os.path.exists(os.path.join('.git', 'MERGE_MSG'))
         yield