@JExercise(
tests = "String pop()",
description =
"The pop() method returns the element on the top of the stack or null if the stack is empty.")
public void testPop() {
assertEquals("pop() should return null when the stack is empty. ", null, stack.pop());
stack.push("0");
stack.push("1");
stack.push("2");
assertEquals("2", stack.pop());
assertEquals("1", stack.pop());
stack.push("3");
assertEquals("3", stack.pop());
assertEquals("0", stack.pop());
assertEquals("pop() should return null when the stack is empty. ", null, stack.pop());
}
@JExercise(
tests = "void push(String)",
description = "The push(String) method puts the String argument on the stack.")
public void testPush() {
stack.push("1");
assertEquals("1", stack.peek(0));
stack.push("2");
assertEquals("2", stack.peek(0));
stack.push("3");
assertEquals("3", stack.pop());
}