Add timeout support

[TApplencourt]

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Hi,

The PR tries to fix #396. It adds a global timeout options (-E <second>) to ./bin/bats.
This option adds a timeout to each test. If a test takes longer than the timeout, it will be killed and will exit with an error code set at 141. In the case of the --tap formater, a # timetout will be printed in the terminal (similar to the #skip behavior)

Technical detail

The implementation is inspired by the great work of https://github.com/MountainField/bash-timeout.
I did tweak it a little bit so it works on my SUSE system. The main idea is to spawn a subprocess who will sleep and kill himself and his parents when waking up.

Summary

I'm not a bash expert, nor a bats one. But I implemented a version of timeout that worked for my use case, and maybe also useful for other people.

Please don't hesitate if you have any feedback, I will be happy to do any modification to the PR to make it more "professional",

Hope this help,
Regards@

[TApplencourt]

Fixed the errors reported by the CI. Sorry about that. All the 178 Tests are now passing on my machine.

I don't think I fixed the contribution error, but I'm not sure how to do it to be honest

EDIT: Test didn't pass on Ubuntu / Windows, I have no idea why... Any help welcomed

[martin-schulze-vireso]

Using SIGPIPE might interfere with some user scripts. I would propose to use SIGALRM or SIGUSR1/2. Furthermore, I think we should name the variable BATS_TEST_TIMEOUT to allow for other kinds of timeouts later on (like setup/setup_file,....)

[TApplencourt]

Thanks a lot for the review.

Using SIGPIPE might interfere with some user scripts. I would propose to use SIGALRM or SIGUSR1/2

I spent a few hours today trying to do so but wasn't successful. My trap was either never called or without a trap, I got some error message corresponding to the trap call. Will potentially invest more time later :)

Furthermore, I think we should name the variable BATS_TEST_TIMEOUT to allow for other kinds of timeouts later on (like setup/setup_file,....)

Good idea will do!

[martin-schulze-vireso]

I already have some local changes for that. I am not sure how to proceed with the traps but will try my own solution

[martin-schulze-vireso]

Sigh, Windows does not support SIGUSR1/2. SIGALRM interferes with sleep. I chose SIGABRT now in the hope of not needing it in the test itself. It may still be interfered with from user code sending it...