Please see the below link. This is how devices are tested for FCC compliance.
http://ecee.colorado.edu/~ecen4517/materials/refs/standards/ANSI_C63.4-2003.pdf
Thank you WDCX for the two excellent documents linked, as they will be of perpetual value to the Part 15 community.
Maybe it's the complexity of these standards that motivates cheap Chinese manufacturers to ignore them?
The next time anyone is tempted to buy a $5 USB power supply wall wart, first take some time to look at some of the YouTube "teardown" videos. They show you exactly what's inside. Some of them are just plain scary.
The Chinese manufacturers and Wal-Mart keep several steps ahead of the FCC by changing their model numbers every few weeks. When the FCC finally gets around to ordering them to stop selling Model #xxxxx, they just say "Yes sir. Already done".