Audio tests take too long to run

[qcapen]

The audio tests take too long to run. Here are the test run times on my computer:
1:17
0:16
0:02
0:02
0:01
0:33
0:22

That's a total of 2:33, which is too long (IMHO). The tests could be shorted by shortening the audio clips used and then adjusting the times in the tests themselves.