NullPointerException expected =
        assertThrows(NullPointerException.class, () -> checkNotNull(null, FORMAT, 5));
    verifyComplexMessage(expected);
  }

  public void testCheckElementIndex_ok() {
    assertEquals(0, checkElementIndex(0, 1));
    assertEquals(0, checkElementIndex(0, 2));
    assertEquals(1, checkElementIndex(1, 2));
  }

  public void testCheckElementIndex_badSize() {