Please try to use the following idom for testing (as I suggested a few times).

    final MultiMap mm = client.getMultiMap(randomString());
    final Object key = "KeyNotLocked";

    boolean result = mm.isLocked(key);

    assertFalse(false);

This makes a test easier to read because you see the 'do' part and the 'assert' part and they are clearly separated.