JUnit测试Try / Catch异常

Question

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?

Answer 1

First of all, you will need to throw the exception in order to catch it in your JUnit test:

public void doUpdateStocks() throws MethodException { // throw the exception
    for (Entry<Integer, IFolioRestricted> e : folioList.entrySet()) {

    IFolioRestricted folio = e.getValue();

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

You code should than work already, but you will have to fail the test, if no exception is thrown:

try {
    h.doBuyStock(0, "A", 10);
    // No exception thrown, thats wrong so fail the test
    Assert.fail()
} catch (IOException | WebsiteDataException | NoSuchTickerException | MethodException e) {
    // This is where you want to end
}

Answer 2

Besides throw the exception (which you definitely have to do), there is a better approach to handle exceptions on unit tests using https://github.com/Codearte/catch-exception

Look at the samples on github.