Problem with Unittest - Thanks:

[Bengt Richter]

On Wed, 14 May 2003 14:26:52 -0400, "Terry Reedy" <tjreedy at udel.edu> wrote:

>
>"Frithiof Andreas Jensen" <frithiof.jensen at removethis.ted.ericsson.dk>
>wrote in message news:b9tn02$5ac$1 at newstree.wise.edt.ericsson.se...
>>
>> Is it legal, moral and commendable to raise exceptions like: 'raise
>> ValueError('some explanation text')?
>
>For the dubious: Ref Manual, 6.9 The raise statement
>"Otherwise, raise evaluates its first expression, which must yield a
>string, class, or instance object. .... If the first expression is an
>instance object, the second expression must be None."   [or omitted,
>unless third expression is present]
>
>try:
>    raise Exception("Test of instance raising")
>except Exception, haha:
>    print haha, type(haha)
>
>#prints
>Test of instance raising <type 'instance'>
>
I'm not sure what you are demonstrating, other than that it's legal ;-) I.e.,
you would get the same haha instance if you raised Exception with a comma and the string.

Anyway, some additional things to notice:

 >>> class Classic:
 ...     def __init__(self, *args): self.args = args
 ...     def __str__(self): return  '<[Classic %r]>' % `self.args`
 ...
 >>> class NewStyle(object):
 ...     def __init__(self, *args): self.args = args
 ...     def __str__(self): return  '<[NewStyle %r]>' % `self.args`
 ...
 >>> for x in [Classic, Classic(1), Classic(1,2,3), NewStyle, NewStyle(1,2,3)]:
 ...     try:
 ...         raise x
 ...     except Classic, e:
 ...         print '%s! : %s\n    args: %r' %  (e.__class__.__name__, e, e.args)
 ...     except Exception, e:
 ...         print '%s! : %s\n    args: %r' %  (e.__class__.__name__, e, e.args)
 ...     except:
 ...         print sys.exc_info()
 ...
 Classic! : <[Classic '()']>
     args: ()
 Classic! : <[Classic '(1,)']>
     args: (1,)
 Classic! : <[Classic '(1, 2, 3)']>
     args: (1, 2, 3)
 TypeError! : exceptions must be strings, classes, or instances, not type
     args: ('exceptions must be strings, classes, or instances, not type',)
 TypeError! : exceptions must be strings, classes, or instances, not NewStyle
     args: ('exceptions must be strings, classes, or instances, not NewStyle',)

Regards,
Bengt Richter