public void Peek_PushTwoElements_ReturnsHeadItem()
{
var stack = new MyStack <int>();
stack.Push(1);
stack.Push(2);
Assert.AreEqual(2, stack.Peek());
}
public void Peek_PushTwoItemsAndPop_ReturnsHeadElement()
{
var stack = new MyStack <int>();
stack.Push(1);
stack.Push(2);
stack.Pop();
Assert.AreEqual(1, stack.Peek());
}