For a resistor nominal test DC. But, it could be 18Ghz or 20 Khz, depending of your application.
For capacitor or self, nominal test is usually1 Khz or 100/120 Hz above 100000pf. Refer to the datashet of the manufacturer : it gives the conditions of mesurement. Again it could be 18 Ghz... (for instance chip capacitor for microwave : usually in form of S parameters)