Exception matcher in Specs BDD library for Scala

Question

Im using the Specs BDD library for writing Scala unit tests (http://code.google.com/p/specs) .In my code if i want to assert that a throws an exception of type ClassNotFoundException, then i can write the following code:

a must throwA[ClassNotFoundException]

However,i want to test the reverse case,i.e.i want to assert that a "does not" throw an exception of type ClassNotFoundException.

I tried using not negation matcher, as follows:

 a must throwA[ClassNotFoundException].not

But that didnt work. Im getting compilation errors. So, is there any way i can assert that an exception of type ClassNotFoundException for example, is not thrown ?

Please Help Thank You

Answer 1

Even if it does not answer to your issue, you do not have to test if no exception is thrown. In this case, you'd better check if the intended result is ok... As soon as the test is executed, it means that it does not throw an exception.

Answer 2

How about something like this:

"An isSpaceNode function" should {
    "not fail with a Group" in {
       Group(<a/><b/>).isSpaceNode must not throwA(new UnsupportedOperationException)
    }
}

Answer 3

The test below passes, if the the expression throws anything except for ClassNotFoundException:

 must throwA[Exception].like {
    case m:  ClassNotFoundException => false
    case _ => true}

If you simply want to make sure that the expression doesn't throw ClassNotFoundException, why not just using try-catch block:

try{
         ...
    }catch{
        case m:  ClassNotFoundException => fail("ClassNotFoundException")
        case e => e.printStackTrace
}

Answer 4

Yes there is a parsing issue when compiling:

 a must throwA[ClassNotFoundException].not

You need to write instead:

 a must not(throwA[ClassNotFoundException])