  The fast flavor instability (FFI) is expected to be ubiquitous in
core-collapse supernovae and neutron star mergers. It rapidly shuffles neutrino
flavor in a way that could impact the explosion mechanism, neutrino signals,
mass outflows, and nucleosynthesis. The variety of initial conditions and
simulation methods employed in simulations of the FFI prevent an
apples-to-apples comparison of the results. We simulate a standardized test
problem using five independent codes and verify that they are all faithfully
simulating the underlying quantum kinetic equations under the assumptions of
axial symmetry and homogeneity in two directions. We quantify the amount of
numerical error in each method and demonstrate that each method is superior in
at least one metric of this error. We make the results publicly available to
serve as a benchmark.
