svoid test_findBestThreshold() {
  testFunctionValues_twoArgs_flat findBestThreshold(
    ll(1.0, 3.0, 5.0), ll(7.0, 8.0), t3(6.0, 0, 0),
    ll(1.0, 3.0, 5.0, 6.0, 10.0), ll(6.5, 7.0, 8.0), t3(6.25, 1, 0),  
    ll(1.0, 3.0, 5.0, 6.0), ll(2.5, 6.5, 7.0, 8.0), t3(6.25, 0, 1),
    ll(1.0, 3.0, 5.0, 99.0, 100.0), ll(1.0, 2.5, 7.0, 8.0), t3(6.0, 2, 2),
  );
}