@Test
    public void numberOfFigureOnBoard() {
        HashSet<String> boards = new HashSet<>();
        boards.add("nnnnnn\n" +
                   "nnnnnn\n" +
                   "nnnnnn\n" +
                   "nnnnnn\n" +
                   "nnnnnn\n" +
                   "nnnnnn\n");

        HashMap<String, Integer> figureQuantityMap = new HashMap<>();
        figureQuantityMap.put(BISHOP.toString(), 3);

        FiguresChain figuresChain = new Bishop(figureQuantityMap);
        Set<String> result = figuresChain.placeFigures(boards.stream()).collect(Collectors.toSet());

        assertThat("there are no boards", result.size() > 0, is(true));
        assertTrue("all elements are not present on each board", result.stream()
                .allMatch(board -> !board.contains(KING.getFigureAsString())
                        && !board.contains(QUEEN.getFigureAsString())
                        && !board.contains(ROOK.getFigureAsString())
                        && !board.contains(BISHOP.getFigureAsString())
                        && board.contains(KNIGHT.getFigureAsString())
                        && leftOnlyFigures(board).length() == 36
        ));

    }