A method of testing a non-volatile memory device on a wafer is disclosed. The method includes performing an erase operation and a first verify operation about every memory cell in the non-volatile memory device, storing data of a first latch in a page buffer for storing result in accordance with the first verify operation in a second latch, and setting the data of the first latch to data indicating pass of the verifying, and performing a soft program and a second verify operation about every memory cell.