[PATCH] iotests: Consistent $IMGOPTS boundary matching

[Max Reitz]

To disallow certain refcount_bits values, some _unsupported_imgopts
invocations look like "refcount_bits=1[^0-9]", i.e. they match an
integer boundary with [^0-9].  This expression does not match the end of
the string, though, so it breaks down when refcount_bits is the last
option (which it tends to be after the rewrite of the check script in
Python).

Those invocations could use \b or \> instead, but those are not
portable.  They could use something like \([^0-9]\|$\), but that would
be cumbersome.  To make it simple and keep the existing invocations
working, just let _unsupported_imgopts match the regex against $IMGOPTS
plus a trailing space.

Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
Supersedes "iotests: Fix unsupported_imgopts for refcount_bits", and can
be reproduced in the same way:

$ ./check -qcow2 -o refcount_bits=1 7 15 29 58 62 66 68 80

(those tests should be skipped)
---
 tests/qemu-iotests/common.rc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 77c37e8312..65cdba5723 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -885,7 +885,9 @@ _unsupported_imgopts()
 {
     for bad_opt
     do
-        if echo "$IMGOPTS" | grep -q 2>/dev/null "$bad_opt"
+        # Add a space so tests can match for whitespace that marks the
+        # end of an option (\b or \> are not portable)
+        if echo "$IMGOPTS " | grep -q 2>/dev/null "$bad_opt"
         then
             _notrun "not suitable for image option: $bad_opt"
         fi
-- 
2.29.2