public void Add()
{
Tree testTree = new Tree();
Assert.IsFalse(testTree.IsExists(1));
testTree.Add(1);
Assert.IsTrue(testTree.IsExists(1));
}
public void Del()
{
Tree testTree = new Tree();
testTree.Add(1);
testTree.Add(2);
testTree.Add(3);
testTree.Delete(2);
Assert.IsTrue(testTree.IsExists(1));
Assert.IsFalse(testTree.IsExists(2));
Assert.IsTrue(testTree.IsExists(3));
}