JUnit testing Try/Catch exception

I can't seem to be able to access the Exception in the method for a JUnit test. Here is the method:

public void doUpdateStocks() {
    for (Entry<Integer, IFolioRestricted> e : folioList.entrySet()) {

        IFolioRestricted folio = e.getValue();

        for(Entry<Integer, IStockRestricted> s : folio.getStockList().entrySet()){
            try {
                ((IStock) (s.getValue())).updatePrice();
            } catch (MethodException e1) {
                e1.printStackTrace();
            }
        }
    }

And this is how I am testing it:

    @Test
    public void testUpdateStock() {

        h.doCreateNewFolio("a");
        try {
            h.doBuyStock(0, "A", 10);
        } catch (IOException | WebsiteDataException | NoSuchTickerException | MethodException e) {
            // TODO Auto-generated catch block
        }
        h.doUpdateStocks();
    }

After looking online I have seen (expected = MethodException.class) however it doesn't seem to work. Anyone any ideas on how to cover the catch (MethodException e1) { e1.printStackTrace(); } in a JUnit?