The present invention relates to an ice maker for a refrigerator and a method of testing the ice maker, and more particularly, to an ice maker for use in a refrigerator for making and releasing ice and a method of testing the ice maker to determine whether the ice maker is normally operated. The fiber module defines a plurality of receiving holes and at least one first positioning hole. The block PN generator generates a section of PN sequence at the end of every symbol period with feedback logic to shift a block of chips each time. Therefore, the accuracy of the data is maintained and the readingwriting speed is increased.