When a TTY is attached to the test unit, grep -q will generate SIGPIPE
for the previous command in the pipeline which in combo with `pipefail`
will cause the command to fail with exit status 141 which will fail the
test.
Replace with >/dev/null to avoid this from happening.
See also https://www.gnu.org/software/grep/manual/html_node/Usage.html
> There is a related problem with Bash’s set -e -o pipefail. Since grep
> does not always read all its input, a command outputting to a pipe read
> by grep can fail when grep exits before reading all its input, and the
> command’s failure can cause Bash to exit.
Co-authored-by: Yu Watanabe <watanabe.yu+github@gmail.com>
If the target dir is tmpfs and we run on old kernels we cannot extract
xattrs and the extracting will fail if there are any. hence add
-no-xattrs to the two remaining unsquashfs invocations that don't have
it.
(Also all other invocations across our test tree spell "-dest" instead
of "-d", hence do so here too.)