assertEquals("size1Queue.peek() should return first element", e0(), getQueue().peek());
    expectUnchanged();
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  @CollectionSize.Require(SEVERAL)
  public void testPeek_sizeMany() {
    assertEquals("sizeManyQueue.peek() should return first element", e0(), getQueue().peek());
    expectUnchanged();
  }