tests: more automated quote adjustment

Relax initial regexp to match more instances, but add a
filter to avoid some invalid conversions.  Run this:

git grep -l "\`[^']*'" tests | xargs perl -pi -e '$q=q"'\''";' \
  -e '$q="$q\\$q$q"; /(= ?\`|\`expr|\`echo|\Q$q\E)/ and next;' \
  -e ' s/\`([^'\''"]*?'\'')/'\''$1/g'
The last disjunct in the above (...) filter is to exempt
any line that contains this string: '\''
With quoting like that, converting a ` to ' is likely to cause trouble,
so we'll handle those manually.  Here are three examples where
the exemption is required:

  *': `link-to-dir/'\'': hard link not allowed for directory'*) ;;
  printf 'creating file `%s'\''\n' $f
  'mv: inter-device move failed: `%s'\'' to `%s'\'';'\

1 files changed, 6 insertions, 6 deletions

diff --git a/tests/misc/sort-merge b/tests/misc/sort-merge
index 3303d10af..8cdde1875 100755
--- a/tests/misc/sort-merge
+++ b/tests/misc/sort-merge
@@ -42,12 +42,12 @@ my @Tests =
 
      # check validation of --batch-size option
      ['nmerge-0', "-m --batch-size=0", @inputs,
-        {ERR=>"$prog: invalid --batch-size argument `0'\n".
-              "$prog: minimum --batch-size argument is `2'\n"}, {EXIT=>2}],
+        {ERR=>"$prog: invalid --batch-size argument '0'\n".
+              "$prog: minimum --batch-size argument is '2'\n"}, {EXIT=>2}],
 
      ['nmerge-1', "-m --batch-size=1", @inputs,
-        {ERR=>"$prog: invalid --batch-size argument `1'\n".
-              "$prog: minimum --batch-size argument is `2'\n"}, {EXIT=>2}],
+        {ERR=>"$prog: invalid --batch-size argument '1'\n".
+              "$prog: minimum --batch-size argument is '2'\n"}, {EXIT=>2}],
 
      ['nmerge-neg', "-m --batch-size=-1", @inputs,
         {ERR=>"$prog: invalid --batch-size argument '-1'\n"}, {EXIT=>2}],
@@ -57,7 +57,7 @@ my @Tests =
 
      ['nmerge-big', "-m --batch-size=$bigint", @inputs,
         {ERR_SUBST=>'s/(current rlimit is) \d+/$1/'},
-        {ERR=>"$prog: --batch-size argument `$bigint' too large\n".
+        {ERR=>"$prog: --batch-size argument '$bigint' too large\n".
               "$prog: maximum --batch-size argument with current rlimit is\n"},
         {EXIT=>2}],
 
@@ -68,7 +68,7 @@ my @Tests =
      # temp files are needed
      ['nmerge-no', "-m --batch-size=2 -T$badtmp", @inputs,
         {ERR_SUBST=>"s|': .*|':|"},
-        {ERR=>"$prog: cannot create temporary file in `$badtmp':\n"},
+        {ERR=>"$prog: cannot create temporary file in '$badtmp':\n"},
         {EXIT=>2}],
 
      # This used to fail because setting batch-size without also setting