CODEWITHSUNDEEP
javajunitassert
Pan
Pan

Reputation: 6655

Asserting in the example below

testLogicalDoc = new LogicalDocumentImpl(-4);  
assertTrue(testLogicalDoc==null);

In my code above, I have an assert condition with which I want to make sure I don't create my object with negative size. It is a stringBuilder beneath the covers which throws NegativeArrayBoundsException for a size less than zero. But my junit test fails here. I don't know any other way of making sure an object is not created with a negative size. Any thoughts on how this could be tested ? or should it be a Junit test at all ??

Many thanks,
-Pan
EDIT: 

 @Test(expected=NegativeArraySizeException.class)  
 public void testCreate4b()  
    {  
            LogicalDocumentImpl testLogicalDoc = new LogicalDocumentImpl(-4);  

    }

I'm catching the exception in the LogicalDocumentImpl class but still this test fails with an assertion error but only succeeds when I do a try catch on assertion error ..why is that so ??

Upvotes: 2

Views: 543

Answers (3)

michid
michid

Reputation: 10834

Catch AssertionError and fail otherwise:

try {
    LogicalDocumentImpl testLogicalDoc = new LogicalDocumentImpl(-4);  
    fail("should throw");
}
    catch (AssertionError e) {
}

Upvotes: 1

Sandro
Sandro

Reputation: 2259

Usually Junit test cases are meant to test that the behavior of your code in certain cases is what you expect. Therefore, for this case you expect that an exception be thrown.

Looking at the JUnit faq (http://junit.sourceforge.net/doc/faq/faq.htm#tests_7) you want to use something like the following:

@Test(expected=NegativeArrayBoundsException.class)

Upvotes: 1

Teja Kantamneni
Teja Kantamneni

Reputation: 17492

if you are throwing NegativeArrayBoundsException your test case could check like this

@Test(expected= NegativeArrayBoundsException.class)

That means your test should throw the exception NegativeArrayBoundsException.

Alternatively you can use fail('should never come here for negative values..')

testLogicalDoc = new LogicalDocumentImpl(-4);  
fail('should never come here for negative values..');

Upvotes: 5

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