diff -r f449138a52df -r 4223bef1489c mercurial/crecord.py
--- a/mercurial/crecord.py	Mon Feb 26 16:22:15 2018 +0530
+++ b/mercurial/crecord.py	Mon Feb 26 18:00:29 2018 +0530
@@ -547,7 +547,7 @@
     chunkselector = curseschunkselector(headerlist, ui, operation)
     if testfn and os.path.exists(testfn):
         testf = open(testfn)
-        testcommands = map(lambda x: x.rstrip('\n'), testf.readlines())
+        testcommands = [x.rstrip('\n') for x in testf.readlines()]
         testf.close()
         while True:
             if chunkselector.handlekeypressed(testcommands.pop(0), test=True):