tests: make test-simplemerge use absolute_import

tests/test-check-py3-compat.t

@@ -61,7 +61,6 b''
   tests/test-lrucachedict.py requires print_function
   tests/test-manifest.py not using absolute_import
   tests/test-pathencode.py not using absolute_import
-  tests/test-simplemerge.py not using absolute_import
   tests/test-trusted.py requires print_function
 
 #if py3exe

tests/test-simplemerge.py

@@ -13,10 +13,16 b''
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import absolute_import
+
 import unittest
-from unittest import TestCase
-from mercurial import util, simplemerge, error
+from mercurial import (
+    error,
+    simplemerge,
+    util,
+)
 
+TestCase = unittest.TestCase
 # bzr compatible interface, for the tests
 class Merge3(simplemerge.Merge3Text):
     """3-way merge of texts.