In this paper, we present a simulation framework for a digital prism-based wavefront sensor. In simulation, we generate a digital prism wavefront sensor (3-sided, 4-sided and cone) and compute the linearity of the 3-sided digital prism wavefront sensor to the defocus aberration. We then use the same simulation tools, replacing the prism WFS phase map with a spatial light modulator in a laboratory set-up. This allows us to create a digital prism-based wavefront sensor in the laboratory. We then evaluate the linearity of a real 3-sided digital prism-based wavefront sensor and compare with our simulations.