@Test
public void testUndo() {

	String[] before = {
			".....",
			"..O..",
			".....",
			"..#..",
			".....",
	};
	player.clear();
	assertFalse(player.undo());
	player.getBoard().setUpProblem(before, BLACK);
	player.acceptMove(at("e3"));
	long fancyHash = player.getBoard().getFancyHash();
	player.acceptMove(at("e1"));
	assertTrue(player.undo());
	assertEquals(fancyHash, player.getBoard().getFancyHash());
	String[] after = {
			".....",
			"..O..",
			"....#",
			"..#..",
			".....",
	};
	assertEquals(asOneString(after), player.getBoard().toString());
}