@Test
    void testGeneralMutability() {
        AndItem a = new AndItem();
        assertFalse(a.isLocked());
        a.lock();
        assertFalse(a.isLocked());
    }
Check basic contracts common to "many" item implementations.

@author Steinar Knutsen
container-search/src/test/java/com/yahoo/prelude/query/ItemsCommonStuffTestCase.java