Tests fail frequently

[J0WI]

The tests fail frequently with the following error:

$ ~/official-images/test/run.sh "$image-passenger"
testing redmine:3.4-passenger
	'utc' [1/5]...passed
	'cve-2014--shellshock' [2/5]...passed
	'no-hard-coded-passwords' [3/5]...passed
	'override-cmd' [4/5]...passed
	'redmine-basics' [5/5]....write /dev/stdout: broken pipe
failed
The command "~/official-images/test/run.sh "$image-passenger"" exited with 1.

At times it's working, so the result seems not to be reliable.

[tianon]

Agreed, I've seen this same flakiness a lot myself; the test itself is in https://github.com/docker-library/official-images/blob/13bfb33799ee45494f6ac815aa8a3368ed1d8888/test/tests/redmine-basics/run.sh, so if there are any ideas for what's making it so flakey, I'd love to get it fixed.

[tianon]

Oh, I think I just figured it out! I think this is a race between docker run and grep -q -- when grep -q finds a match, it will exit immediately and close the input file (which in this case is Docker's stdout), which causes docker run to balk with this error message. Fix incoming.

[tianon]

docker-library/official-images#4721 👍