JUnit in action: does it cover how to handle exceptions correctly?

[bengt hammarlund]

hi there! I have a question to the author: does your book cover how to correctly test methods that throw exceptions?
I've testing methods that throw exceptions like this:
- at first, I simply write a testXXX() throws Exception{}
- then, I write code that should throw an exception, an I catch it. But the testXXX() still throws exceptions, so I can test that my method really is throwing the right exception.
Is this procedure ok, or is there any other ideias in the book? Thanks for any reply!
I think exceptions are a very important issue, and something not that easy to test sometimes.
[ November 06, 2003: Message edited by: bengt hammarlund ]

[Jeanne Boyarsky]

Bengt,
If the method could throw an exception, but you don't expect it to, testXXX() throws Exception{} is fine. If you want to test that the code throws a certain exception, you can use code of the form.

public void testXXX() {
  try {
    callToCodeThrowingException();
    fail("should throw exception");
  } catch (ExpectedException e) {
     // expected
  } catch (Exception e) {
    fail("should throw ExpectedException");
  }
}

[Vincent Massol]

Originally posted by bengt hammarlund:
hi there! I have a question to the author: does your book cover how to correctly test methods that throw exceptions?
I've testing methods that throw exceptions like this:
- at first, I simply write a testXXX() throws Exception{}
- then, I write code that should throw an exception, an I catch it. But the testXXX() still throws exceptions, so I can test that my method really is throwing the right exception.
Is this procedure ok, or is there any other ideias in the book? Thanks for any reply!
I think exceptions are a very important issue, and something not that easy to test sometimes.
[ November 06, 2003: Message edited by: bengt hammarlund ]

Yes the book does cover it. Actually in most places you'll find that it shows how to test for positive and error paths. What you're doing seems right. There are several other best practices as discussed in the book, like use "expected" as the name of the exception you're expecting, etc.

[Anil Vupputuri]

Hi Vincent,
Haven't used JUnit yet, just getting started. Which type of testing wud you suggest, is it GUI based or Text based (customizing Ant scripts).
Thanks.

[Lasse Koskela]

Originally posted by Anil Vupputuri:
Which type of testing wud you suggest, is it GUI based or Text based (customizing Ant scripts).

Both, I'd say. Have your Ant script run all the tests when making a build, and run a subset of the tests from your IDE while developing.