@Test
public void deleteAllTest() throws NoSuchFieldException, IllegalAccessException {

    addItem(AID_BASIC, HASH_BASIC, RULE_BASIC);
    addItem(AID_BASIC1, HASH_BASIC1, RULE_BASIC1);
    addItem(AID_BASIC2, HASH_BASIC2, RULE_BASIC2);
    addItem(AID_BASIC3, HASH_BASIC3, RULE_BASIC3);
    RuleEntry.deleteAll();
    assertEquals("length after deletion", 0, getLength());
}