test: Add PCM interface tests

alsa-project/alsa-lib pull request #359 was opened from smelamud:

Add tests for various features of the PCM interface. The goal is to maximize coverage of the corresponding kernel code. The tests use a loopback device and require snd-aloop kernel module to be loaded.

Request URL : https://github.com/alsa-project/alsa-lib/pull/359 Patch URL : https://github.com/alsa-project/alsa-lib/pull/359.patch Repository URL: https://github.com/alsa-project/alsa-lib