updated for version 7.3.392
Problem:    When setting 'undofile' while the file is already loaded but
            unchanged, try reading the undo file. (Andy Wokula)
Solution:   Compute a checksum of the text when 'undofile' is set. (Christian
            Brabandt)
diff --git a/src/testdir/test72.in b/src/testdir/test72.in
index 6acb6d8..220adad 100644
--- a/src/testdir/test72.in
+++ b/src/testdir/test72.in
@@ -51,6 +51,12 @@
 :e Xtestfile
 uuu:w >>test.out
 :"
+:" Test that reading the undofiles when setting undofile works
+:set noundofile ul=0
+i
+u:e! Xtestfile
+:set undofile ul=100
+uuuuuu:w >>test.out
 :" And now with encryption, cryptmethod=zip
 :e! Xtestfile
 :set undofile cm=zip