An automated pulse current testing of the laser diode is presented. Built around an accurate and fast rise time pulse generator and a minicomputer, it has been used to test several laser diodes to extract characteristics such as threshold current and thermal resistance. The computer-controlled pulse generator offers multivariable control of output pulse. Control and data acquisition algorithms were developed in a low level language, MACRO11, to enhance speed and resource utilization, and in FORTRAN, which facilitated the man/machine interface or manware. Continuous wave and pulse test results are compared to illustrate the heating effects.