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),  
  );
}