svoid test_AllOnAll_probabilistic() {
  new AllOnAll_probabilistic<Int, Int> aoa;
  aoa.addA(2);
  aoa.addA(4);
  aoa.addB(6);
  aoa.addB(100);
  aoa.addB(95);
  aoa.addB(30);
  aoa.probabilityForPair = (a, b) -> (double) a*b;
  assertEqualsVerbose(tlft([[
    <4, 100>
    <4, 95>
    <2, 100>
    <2, 95>
    <4, 30>
    <2, 30>
    <4, 6>
    <2, 6>
  ]]),
  tlft(hijackPrint(r { printWhileNotNull(() -> aoa.next()) })));
}