Keep in mind that there is a difference between Unit Testing, which is the act of writing small tests that test individual units of your code, and Automated Test Runners which run your unit tests, usually as part of the build process or some kind of continuous integration system.

Unit testing is commonly automated, but may still be performed manually. The IEEE does not favor one over the other. The objective in unit testing is to isolate a unit and validate its correctness. A manual approach to unit testing may employ a step-by-step instructional document.

(http://en.wikipedia.org/wiki/Unit_testing#Techniques)

You can easily write a unit test to test that an audio player component plays audio correctly:

1. Make sure your speakers are working and the volume is turned up.
2. Go to /my/test/folder.
3. Execute myTestRunner audioPlayerTest.script.thingee.
4. You should hear Beethoven's 5th Symphony play for 15 seconds.
5. If you heard nothing, the audio played more or less than 15 seconds, or was distorted in any way, the test failed. Otherwise, the test passed.

What you can't easily do is include that test in an automated testing system. Automated testing is a particular implementation of unit testing, but it isn't the only implementation.

See also: http://stackoverflow.com/questions/1877118/is-unit-testing-always-automated

Keep in mind that there is a difference between Unit Testing, which is the act of writing small tests that test individual units of your code, and Automated Test Runners which run your unit tests, usually as part of the build process or some kind of continuous integration system.

Unit testing is commonly automated, but may still be performed manually. The IEEE does not favor one over the other. The objective in unit testing is to isolate a unit and validate its correctness. A manual approach to unit testing may employ a step-by-step instructional document.

(http://en.wikipedia.org/wiki/Unit_testing#Techniques)

You can easily write a unit test to test that an audio player component plays audio correctly:

1. Make sure your speakers are working and the volume is turned up.
2. Go to /my/test/folder.
3. Execute myTestRunner audioPlayerTest.script.thingee.
4. You should hear Beethoven's 5th Symphony play for 15 seconds.
5. If you heard nothing, the audio played more or less than 15 seconds, or was distorted in any way, the test failed. Otherwise, the test passed.

What you can't easily do is include that test in an automated testing system. Automated testing is a particular implementation of unit testing, but it isn't the only implementation.

See also: https://stackoverflow.com/questions/1877118/is-unit-testing-always-automated