So we can easily find other tools.

Signed-off-by: Marc Herbert <[email protected]>

So we can invoke other tools easily.

Signed-off-by: Marc Herbert <[email protected]>

This all started as an effort to solve test failures caused by "MAX"
volume. See thesofproject#931 and others linked from there for more context.

Another obvious issue was the duplication of `expect` code across two
tests (check-pause-resume.sh and multiple-pause-resume.sh)

After a bit of time actually "testing the tests" I realized the original
author did not really understand `expect` or the problem. So I rewrote
the entire `expect` part. The list of previous issues is a bit too long
not to forget any but here are some:

- The script could get "out of sync" with aplay and report that it was
  paused when it was actually resumed! And vice-versa.

- De-duplication; obviously.

- Moving to a separate script also solves the following problems:
  - Can be invoked, tested and debugged separately outside any shell script
  - Simplifies quoting
  - Unlocks editor features like syntax checking

- Proper understanding and handling of newlines.

- The expect script does not "sleep" anymore, which stops backpressuring
  and blocking the console output from aplay - with unknown side effects!

- Adding `log_user 0` makes the test logs readable at last

- Add decent logging for easier maintenance

- Logging timestamps demonstrate that the entire aproach is too slow for
  pause/resume cycles shorter than ~200 ms. Default values won't be
  changed yet but at least the problem is now obvious.

- Handle "MAX" volume! Not an error yet because it happens really across
  the board (MAX does usualy not happen long enough to timeout and
  _fail_ across the board) but the code is ready to upgrade the "MAX"
  warning to an ERROR with a one-line change.

- Report EOF and timeouts differently.

- Probably others.

Signed-off-by: Marc Herbert <[email protected]>

See long commit message in previous commit adding apause.exp

Signed-off-by: Marc Herbert <[email protected]>

See long commit message in previous commit adding apause.exp

Signed-off-by: Marc Herbert <[email protected]>