public static void OneToOneRelationTest(bool useTuples)
{
var arr = Array.Empty <(int, double)>();
var r = useTuples
? Relations.AsBijective(arr)
: Relations.AsBijective(arr.Select(t => KeyValuePair.Create(t.Item1, t.Item2)));
Assert.Empty(r.Elements);
Assert.False(r.MaybeResult(3).HasValue);
Assert.False(r.Contains(1, 3D));
Assert.False(r.Contains(2, 2D));
Assert.False(r.GetMaybeLeft(3D).HasValue);
Assert.False(r.GetMaybeRight(3).HasValue);
arr = new[] { (1, 2D) };