A testing method includes measuring an electrical parameter of a device under test (DUT) and a corresponding temperature of the DUT one or more times, determining coefficients in a pre-constructed model based on a plurality of measured values of the electrical parameter and corresponding measured temperatures to characterize a relationship of the electrical parameter to the temperature, and determining a quality of the DUT based on the model and a limit value of the electrical parameter at a specified temperature. The model is pre-constructed to characterize the relationship of the electrical parameter to the temperature with the coefficients that are DUT-dependent variables.