Timeout support about assert_cmd

[epage]

See discussion at assert-rs/assert_cli#67

[epage]

From previous thread

Looks like this will be pretty trivial
https://crates.io/crates/wait-timeout

Nevermind, it doesn't support getting the output and it doesn't look like it will in the foreseeable future
alexcrichton/wait-timeout#4

[vincentdephily]

For my use, I'm simply looping through all my currently-live commands and calling thread::sleep(10ms) before looping again. Not pretty but it works. I've found 10ms to be useful even on my slow-ish CI.

A better solution would use futures, but I'm not sure what futures are available to wait for process exit. Presumably, implementing those futures is assrt_cmd's job.

Note that I use a generic CmdCond enum which can describe a timeout condition but also "when that other command has exited" or "when that file matches a predicate".

You can steal code from https://gist.github.com/vincentdephily/592546c41ff9713adff234e5535aa6d4

[dylni]

@epage I created a crate that should help with this:
https://crates.io/crates/process_control

You can use Child::with_output_timeout to get output from a process with a timeout.