@Test
public void testValid() {

	assertTrue( board.valid(L4, 0, 1));
	board.add(L4, 0, 1);
	assertFalse( board.valid(L4, 1, 3));
	assertFalse( board.valid(L4, 1, 4));
	assertFalse( board.valid(L4, 2, 3));
	assertTrue( board.valid(L4, 2, 4));
	board.add(L4, 2, 4);
}