private void testPeek(BasicStack <DSString> the_stack)
{
//check multiple peeks
Assert.AreEqual("9", the_stack.peek().value);
Assert.AreEqual("9", the_stack.peek().value);
//peek after removal
the_stack.pop();
Assert.AreEqual("8", the_stack.peek().value);
//peek with nothing on the stack
while (!the_stack.isEmpty())
{
the_stack.pop();
}
Assert.AreEqual(null, the_stack.peek());
}