@Test
public void testRemoveIf() {

    IntList list = new IntList();
    list.removeIf(o -> o < 7);
    assertThat(list.toArray()).isEmpty();
    list.add(10);
    list.add(5);
    list.removeIf(o -> o < 7);
    assertThat(list.toArray()).containsExactly(10);
}