Index: tests/lit.cfg
===================================================================
--- tests/lit.cfg
+++ tests/lit.cfg
@@ -33,6 +33,10 @@
 except:
     build_root = ''
 config.environment['PYTHONPATH'] = '%s:%s' % (build_root, src_root)
+if 'LANG' in os.environ and os.environ['LANG'].endswith('.UTF-8'):
+    config.environment['LANG'] = os.environ['LANG']
+else:
+    config.environment['LANG'] = 'en_US.UTF-8'
 # Don't generate .pyc files when running tests.
 config.environment['PYTHONDONTWRITEBYTECODE'] = "1"
 config.environment['SUDO_CMD'] = ""