If you can find sample code for a radio test, you may be able to put the radio into compliance test mode. For a Bluetooth radio, you can turn a signal on/off, CW/modulated, set power level, set data speed, etc., on a selected channel. Typically, this would be example code for the chip you're working with. I've never done this on WiFi, however.
Keep in mind that when you are transmitting, you should be in a screen room or RF test box to avoid radiated signals.