I used to test my sound settings with the command
dd if=/dev/urandom of=/dev/dsp
This will play random sound over your default sound device (using OSS).
I am using SUSE Linux. Now in the newer releases (starting maybe 12.1, not sure)
/dev/dsp is no longer there but sound works nevertheless. That is a problem because I have written guides how to troubleshoot sound problems under Linux, e.g. http://www.linuxintro.org/wiki/Sound_troubleshooting
/dev/dsp no longer there by default? How do I do a "smoke test" for Linux sound?