For gravity + zeus + SetAccelerationBoundary, added a modification to Grid_InterpolateBoundaryFromParent that causes staggered interpolation to be performed for Acceleration as well as velocity field types.
The only test in the test suite that seems to employ this machinery is GravityTestSphere. Differences in the solution are minor. The improvement can be seen when examining Level 7 grids for GravityTestSphere. Without this fix, SetAccelerationBoundary causes an even-odd pattern in the low density region, at the grid boundary. With the fix this pattern goes away.
Great! The current quick suite of the test runner gives:
The tests that fail are the new and improved GravityTestSphere and ExtremeAdvectionTest, which in the current gold standard are broken (or run without SAB). I think this is ready to be pulled in, and then the gold standard should be remade.