@Test
public void testRemove() {

    map.put("kEy1", newArrayList("a", "b", "c"));
    map.put("KEy2", newArrayList("e", "f"));
    assertEquals(2, map.size());
    assertEquals(new ArrayList<>(Arrays.asList("e", "f")), map.remove("KEY2"));
    assertEquals(1, map.size());
    assertTrue(map.containsKey("key1"));
    assertFalse(map.containsKey("kEy2"));
}