The 160 MeV H− beam from the Linac4 linear accelerator at CERN will be injected into the Proton Synchrotron Booster with a new H− charge-exchange injection system. It will include a stripping foil, to convert H− into protons by stripping off the electrons. To gain experience with these very fragile foils, prior to the installation in the PSB, and test different foil materials and thicknesses, lifetimes of the foils, the foil changing mechanism and interlocking functions, a stripping foil test stand will be installed in the Linac4 transfer line in 2015. This paper describes the mechanical design of the system and discusses the test possibilities and parameters.