ok    nonmatching partitions geometrically close without normalization
  ok    independent analytic crossing-cell inventory integral
  ok    liquid, both surfactant compartments and momentum all conserved
  ok    constant velocity preserved even for unequal masses and nonmatching partitions
  ok    opposing momenta mix without artificial kinetic-energy injection
  ok    transfer commutes with an arbitrary uniform velocity boost
  ok    moving interface swept ownership matches independent half-cell integral
  ok    shared interface inventories cancel with reversed orientation
  ok    uncovered domain rejected rather than renormalized away
  ok    equal total area cannot hide overlapping cells plus a hole
  ok    reversed polygon rejected
  ok    negative liquid inventory rejected
  ok    bounded point Voronoi support agrees with independent Cartesian squares
  ok    small translated physical cell area avoids origin cancellation

14 passed, 0 failed