  Moving-puncture coordinates are commonly used in numerical simulations of
black holes. Their properties for vacuum Schwarzschild black holes have been
analyzed in a number of studies. The behavior of moving-puncture coordinates in
spacetimes containing matter, however, is less well understood. In this paper
we explore the behavior of these coordinates for Oppenheimer-Snyder collapse,
i.e., the collapse of a uniform density, pressureless sphere of dust initially
at rest to a black hole. Oppenheimer-Snyder collapse provides a stringent test
of the singularity-avoiding properties of moving-puncture coordinates, since
the singularity can form more quickly than it would for matter with pressure.
Our results include analytical expressions for the matter density, lapse
function, and mean curvature at early times, as well as interesting limits for
later times. We also carry out numerical simulations to obtain the full
solution and these show that, even in the absence of pressure, moving-puncture
coordinates are able to avoid the singularity. At late times the geometry
settles down to a trumpet slice of a vacuum black hole.
