public void DifferentialTest()
{
TupleDescriptor descriptor = TupleDescriptor.Create(fieldTypes);
Xtensive.Tuples.Tuple t1 = Tuple.Create(descriptor);
Xtensive.Tuples.Tuple t2 = t1.Clone();
PopulateData(fieldTypes, t2, t1);
DifferentialTuple d = new DifferentialTuple(t1);
AssertAreSame(t1, d);
PopulateData(fieldTypes, t1, d);
AssertAreSame(t1, d);
DifferentialTuple c = (DifferentialTuple)d.Clone();
AssertAreSame(d, c);
d.Reset();
AssertAreSame(t2, d);
AssertAreSame(t1, c.ToRegular());
}