Production testing of digitally modulated transceivers such as those based on orthogonal frequency division multiplexing (OFDM) has become challenging, particularly in the context of measuring specifications such as error-vector-magnitude (EVM) which require the use of precision test equipment with digital modulation capability and low noise floor. Moreover, test time is an issue due to the need to transmit and receive a large number of data bits for accurate test measurement. In this paper, a multi-tone based test method is presented for accurately measuring the EVM and noise specifications of a wireless device. We present the theory behind the proposed approach along with simulation results. The proposed test method is low-cost, and has the potential to significantly reduce EVM test time under production test conditions.