@Test public void remove() {

  // internally, remove is never called on odd number, or at or after array length
  {
    Object[] array = new Object[] {1, 2, 3, 4, 5, 6};
    MutableSpan.remove(array, 0);
    assertThat(array).containsExactly(3, 4, 5, 6, null, null);
  }
  {
    Object[] array = new Object[] {1, 2, 3, 4, 5, 6};
    MutableSpan.remove(array, 2);
    assertThat(array).containsExactly(1, 2, 5, 6, null, null);
  }
  {
    Object[] array = new Object[] {1, 2, 3, 4, 5, 6};
    MutableSpan.remove(array, 4);
    assertThat(array).containsExactly(1, 2, 3, 4, null, null);
  }
}