public void TestEndToAssociationResetSet2Set()
{
var model = new MutableModel();
var factory = new PropertiesTestFactory(model);
var assoc = factory.Association();
var end = factory.AssociationEndSet();
end.Association = assoc;
Assert.True(assoc.FirstSet.Count == 1);
Assert.True(assoc.SecondSet.Count == 1);
Assert.Contains(end, assoc.FirstSet);
Assert.Contains(end, assoc.SecondSet);
Assert.Equal(assoc, end.Association);
end.Association = null;
Assert.True(assoc.FirstSet.Count == 0);
Assert.True(assoc.SecondSet.Count == 0);
Assert.Null(end.Association);
var imodel = model.ToImmutable();
var iassoc = assoc.ToImmutable(imodel);
var iend = end.ToImmutable(imodel);
Assert.Null(iassoc.First);
Assert.Null(iassoc.Second);
Assert.Null(iend.Association);
}