"StepH" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > So why the assertRaises function in unittest ? My goal is to test if an > exception is well raised when a bad filename is passed to the mps2xml > function.
It is for functions in which the exception is raised and not caught. You can use the exception mechanism to let the code invoking your function know that something "exceptional" has happened. It means that you "throw" that exception to the invoking code which has to catch it. Maybe the terminology is poorly chosen, but assertRaises does not check whether an exception is raised inside the function but only that an exception is raised (or "thrown", as described by other languages) from inside the function to outside. A function does not "throw" an exception if the exception is caught inside the function. Is that clearer now? In java for instance, functions are actually declared to "throw" an exception if any operation inside the function may throw that exception and the exception is not caught inside the function. If you implement a function A that invokes another function B and B throws an exception of type C, then you must catch the exception C in A or you have to declare A that it "throws C". Hope this helps. Dan -- http://mail.python.org/mailman/listinfo/python-list
