import static org.junit.Assert.*;
import org.junit.Test;
import java.util.Stack;

public class SlowQueueTestReverse {

  @Test
  public void testReverseQueue() {

    SlowQueue<String> q = new SlowQueue<String>();
    q.enqueue("a");
    q.enqueue("b");
    q.enqueue("c");
    q.enqueue("d");

    assertEquals("a", q.peek());

    reverseQueue(q);

    assertEquals("d", q.peek());

    assertEquals("d", q.dequeue());
    assertEquals("c", q.dequeue());
    assertEquals("b", q.dequeue());
    assertEquals("a", q.dequeue());
  }

  private void reverseQueue(SlowQueue<String> qu) {
    Stack<String> s = new Stack<String>();

    while (!qu.isEmpty()) {
      s.push(qu.dequeue());
    }

    while (!s.isEmpty()) {
      qu.enqueue(s.pop());
    }
  }

  @Test
  public void testAllMethods() {
    SlowQueue<String> q = new SlowQueue<String>();
    assertTrue(q.isEmpty());

    q.enqueue("a");
    assertFalse(q.isEmpty());
    assertEquals("a", q.peek());
    q.enqueue("b");
    assertFalse(q.isEmpty());
    assertEquals("a", q.peek());
    q.enqueue("c");
    assertEquals("a", q.peek());
    q.enqueue("d");
    assertEquals("a", q.peek());

    assertEquals("a", q.dequeue());
    assertFalse(q.isEmpty());
    assertEquals("b", q.dequeue());
    assertEquals("c", q.dequeue());
    assertEquals("d", q.dequeue());
    assertTrue(q.isEmpty());
  }
}