1. A test method including: measuring a quiescent power supply current for each test vector switched among a plurality of test vectors, for each of a plurality of samples of a device under test; calculating a statistical quiescent power supply current for each test vector, and creating first array data including identifiers for the test vectors and the statistical quiescent power supply current values as elements; sorting the first array data using the quiescent power supply current value as a key so as to create second array data; calculating the difference in quiescent power supply current, which is obtained by calculating the differences between the adjacent quiescent power supply current elements of the second array data, so as to create third array data including the identifiers for the test vectors and the differences in current value as elements; and sorting the third array data using the difference in current value as a key so as to create fourth array data.