1. A self-synchronous logic circuit having a test function, comprising: registers holding data, connected in a plurality of stages for a pipeline; and self-synchronous signal control circuits provided corresponding to said registers connected in a plurality of stages, respectively; wherein said self-synchronous signal control circuits perform four-way handshake in which, when transfer permission to a preceding stage is applied in a first way, a transfer request from the preceding stage is received as an input together with data output from the register of the preceding stage, upon input of the transfer request, transfer reception is applied to the preceding stage in a second way, when the transfer reception is received as an input by the preceding stage, transfer complete is received as an input from the preceding stage in a third way, and when the transfer complete is received as an input and transfer permission is applied from the succeeding stage in a fourth way, transfer permission is applied to the preceding stage and data from the preceding stage is taken and held by the register and data is output to the succeeding stage to apply transfer request to the succeeding stage; and said registers have a function of successively transferring data in a normal operation and in a test operation; said self-synchronous logic circuit setting all said self-synchronous signal control circuits to a state of the third way of said handshake and thereafter, applying transfer permission and transfer reception to said self-synchronous signal control circuit of the last stage in a test operation.