In this paper we discuss the design, status and goals of the experimental effort by the University of Wisconsin Accelerator Physics group, in collaboration with Argonne Advanced Accelerator group, to test the principle of the Plasma Wakefield Accelerator (PWFA). The test facility constructed at ANL provides a very short (6 psec), intense bunch of electrons at 22 MeV, which is used to excite large amplitude plasma oscillations in a hollow cathode arc plasma. The plasma supported electrostatic wakefields, which can be expected to exceed 100 MeV/m in this experiment, are probed by a low intensity 15 MeV witness pulse with a variable delay time behind the driving bunch. The energy changes and transverse kicks in both beams are measured by a high resolution, double focusing, broad range magnetic spectrometer. This experimental scheme is designed to measure the longitudinal response of the plasma dynamics as well as the radial effects due to the finite transverse beam extent as a first test of the physics of the PWFA.