public void Peek_OnEmptyStack_ReturnExceptionMessage()
{
Stack testStack = new Stack();
string expected = "Stack is empty.";
string actual = testStack.Peek();
Assert.AreEqual(expected, actual);
}
public void Peek_OnPopulatedStack_ReturnString()
{
Node testNode = new Node("test");
Stack testStack = new Stack();
testStack.Push(testNode);
string expected = "test";
string actual = testStack.Peek();
Assert.AreEqual(expected, actual);
}