@SuppressWarnings({
    "SelfEquals", // TODO(cpovirk): Consider using EqualsTester from Guava.
    "UndefinedEquals", // Comparisons of an object to itself *are* defined.
  })
  public void testEquals_self() {
    assertTrue("An Object should be equal to itself.", collection.equals(collection));
  }

  // Comparisons to null *are* defined.
  @SuppressWarnings("UndefinedEquals")
  public void testEquals_null() {