Yet another interview task: Linked list

LinkedList.java

package lab;

public class LinkedList<T> {

	class Node {
		public final T value;
		public final Node prev;
		
		public Node(Node prev, T value) {
			this.prev = prev;
			this.value = value;
		}
	}
	
	Node head;

	public LinkedList() {
	}

	public void push(T value) {
		head = new Node(head, value);
	}

	public T pop() {
		if (head == null) 
			throw new RuntimeException("List is empty");
		T result = head.value;
		head = head.prev;
		return result;
	}
}

LinkedListTest.java

package lab;

import org.junit.Assert;
import org.junit.Test;

public class LinkedListTest {

	@Test
	public void test() {
		LinkedList<Long> linkedList = new LinkedList<Long>();
		try {
			linkedList.pop();
			Assert.fail("Exception expected");
		} catch (RuntimeException e) {
			// expected
		}
		linkedList.push(1L);
		Assert.assertEquals(new Long(1L), linkedList.pop());
		linkedList.push(1L);
		linkedList.push(2L);
		Assert.assertEquals(new Long(2L), linkedList.pop());
		Assert.assertEquals(new Long(1L), linkedList.pop());
		try {
			linkedList.pop();
			Assert.fail("Exception expected");
		} catch (RuntimeException e) {
			// expected
		}
	}
}