"Should be able to peek() middle element multiple times", "B", peekingIterator.peek());
    assertEquals(
        "next() should still return middle element after peeking", "B", peekingIterator.next());

    assertEquals("Should be able to peek() at last element", "C", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() last element multiple times", "C", peekingIterator.peek());
    assertEquals(

        "Should be able to peek() middle element multiple times", "B", peekingIterator.peek());
    assertEquals(
        "next() should still return middle element after peeking", "B", peekingIterator.next());

    assertEquals("Should be able to peek() at last element", "C", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() last element multiple times", "C", peekingIterator.peek());
    assertEquals(

          }
        };

    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.peek());
    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.next());

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    try {
      iter.peek();
      fail("peek() should throw NoSuchElementException at end");

    assertTrue(queue.add("hi"));
    assertEquals("hi", queue.element());
    assertEquals("hi", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

    assertTrue(queue.add("there"));
    assertEquals("there", queue.element());
    assertEquals("there", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

@Throws(EOFException::class)
private fun Buffer.readChallengeHeader(result: MutableList<Challenge>) {
  var peek: String? = null

  while (true) {
    // Read a scheme name for this challenge if we don't have one already.
    if (peek == null) {
      skipCommasAndWhitespace()
      peek = readToken()
      if (peek == null) return
    }

    val schemeName = peek

    // Read a token68, a sequence of parameters, or nothing.

    // other threads waiting on take() will also return.
    if (result == DEAD_LETTER) responseQueue.add(DEAD_LETTER)

    return result
  }

  override fun peek(): MockResponse {
    return responseQueue.peek() ?: failFastResponse ?: super.peek()
  }

  open fun enqueueResponse(response: MockResponse) {
    responseQueue.add(response)
  }

  open fun clear() {
    responseQueue.clear()
  }

          }
        };

    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.peek());
    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.next());

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    try {
      iter.peek();
      fail("peek() should throw NoSuchElementException at end");

	}
	if _, err := buf.Peek(1); err != io.EOF {
		t.Fatalf("want EOF got %v", err)
	}

	// Test for issue 3022, not exposing a reader's error on a successful Peek.
	buf = NewReaderSize(dataAndEOFReader("abcd"), 32)
	if s, err := buf.Peek(2); string(s) != "ab" || err != nil {
		t.Errorf(`Peek(2) on "abcd", EOF = %q, %v; want "ab", nil`, string(s), err)
	}
	if s, err := buf.Peek(4); string(s) != "abcd" || err != nil {

    public boolean remove(Object object) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.remove(object);
    }

    @Override
    public @Nullable E peek() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.peek();
    }

    @Override
    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override

    assertTrue(queue.add("hi"));
    assertEquals("hi", queue.element());
    assertEquals("hi", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());

    assertTrue(queue.add("there"));
    assertEquals("there", queue.element());
    assertEquals("there", queue.peek());
    assertEquals(1, queue.size());
    assertEquals(0, queue.remainingCapacity());