I am testing for Exceptions using unittest, for example:
self.assertRaises(UnrecognizedAirportError, func, arg1, arg2)
and my code raises:
raise UnrecognizedAirportError('From')
Which works well.
How do I test that the argument in the exception is what I expect it to be?
I wish to somehow assert that capturedException.argument == 'From'.
I hope this is clear enough - thanks in advance!
Tal.
Like this.
>>> try:
... raise UnrecognizedAirportError("func","arg1","arg2")
... except UnrecognizedAirportError, e:
... print e.args
...
('func', 'arg1', 'arg2')
>>>
Your arguments are in args, if you simply subclass Exception.
See http://docs.python.org/library/exceptions.html#module-exceptions
If the exception class is derived from the standard root class BaseException, the associated value is present as the exception instance’s args attribute.
Edit Bigger Example.
class TestSomeException( unittest.TestCase ):
def testRaiseWithArgs( self ):
try:
... Something that raises the exception ...
self.fail( "Didn't raise the exception" )
except UnrecognizedAirportError, e:
self.assertEquals( "func", e.args[0] )
self.assertEquals( "arg1", e.args[1] )
except Exception, e:
self.fail( "Raised the wrong exception" )
assertRaises is a bit simplistic, and doesn't let you test the details of the raised exception beyond it belonging to a specified class. For finer-grained testing of exceptions, you need to "roll your own" with a try/except/else block (you can do it once and for all in a def assertDetailedRaises method you add to your own generic subclass of unittest's test-case, then have your test cases all inherit your subclass instead of unittest's).
