A system for testing electronic circuits is configured to receive a test signal and an ideal response signal and output a test result signal. The system for testing electronic circuits includes a circuit portion to be tested, a comparator and a comparison result recorder. The circuit portion to be tested receives a test signal from a test instrument, and outputs a system response signal. The comparator receives the system response signal from the circuit portion to be tested and receives an ideal response signal from the test instrument. Then, the comparator outputs a comparison result according to the system response signal and the ideal response signal. The comparison result recorder receives and records the comparison result. The comparison result recorder may record comparison results within a period of test time. The test instrument can obtain a record of the comparison results from the comparison result recorder.