testscript: signal or some other way to interrupt running command

[ldemailly]

I want to be able to test ^C behavior and long running but interruptible programs and not having a pid from & I don't know how to do it

otherwise testscript is near perfect!

# how to do this
dnsping www.google.com 8.8.8.8 &
exec sleep 3
exec kill %1 # this doesn't exist/work - doesn't reference the dnsping sub process above
wait
stderr 'will query until interrupted'
stdout '0 errors \(0.00%\), [34] success.'

right now I found this workaround but it's brittle (relies on the exec being called same as the go command and nothing else being called same - and also doesn't work on ci)

exec pkill -x dnsping # todo want something like kill %1 instead

https://github.com/fortio/dnsping/pull/17/files#diff-c93182c79a5fb9ceb9b9ba653ab9acd3ea10510a75167c5972e3890fa799389bR76

[ldemailly]

Am I not seeing an existing easy way to achieve this? (got reminded of this reading #228 where setup go side is mentioned but I am also looking for something in txtar)

[mvdan]

Let's consolidate under #242, since that issue has an open PR.