patch 8.0.0032
Problem:    Tests may change the input file when something goes wrong.
Solution:   Avoid writing the input file.
diff --git a/src/testdir/test97.in b/src/testdir/test97.in
index d4ff6d9..5a4cb1e 100644
--- a/src/testdir/test97.in
+++ b/src/testdir/test97.in
@@ -7,7 +7,7 @@
 :set shell=doesnotexist
 :" consistent sorting of file names
 :set nofileignorecase
-:e test.out
+:e! test.out
 :$put =glob('Xxx\{')
 :$put =glob('Xxx\$')
 :w! Xxx{