[ python-Bugs-1009729 ] Cannot doctest a SyntaxError

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Bugs item #1009729, was opened at 2004-08-15 20:20
Message generated for change (Comment added) made by tim_one
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Category: Python Library
>Group: Not a Bug
>Status: Closed
>Resolution: Invalid
Priority: 5
Submitted By: Raymond Hettinger (rhettinger)
Assigned to: Edward Loper (edloper)
Summary: Cannot doctest a SyntaxError

Initial Comment:
Currently, doctests cannot be used to demonstrate or
test that misconstructions produce a syntax error.  I'm
not certain, but I believe that case is trappable and
veriable.  

The following is an actual use case for one of the
tests I would like to have in test.test_genexps.py:


Verify that parenthesis are required in a statement
>>> def f(n):
...     return i*i for i in xrange(n)
...
SyntaxError: invalid syntax

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>Comment By: Tim Peters (tim_one)
Date: 2004-08-15 20:33

Message:
Logged In: YES 
user_id=31435

doctest has always been able to handle SyntaxError; e.g., 
see test_generators.py.

You need a "Traceback:" line too.  This is explained in detail 
in the current (CVS) doctest LaTeX docs.

For example, this spelling works fine as a doctest:

"""
>>> def f(n):
...     return i*i for i in xrange(n)
Traceback (most recent call last):
   ...
SyntaxError: invalid syntax
"""

You can take out the ellipsis between Traceback and 
SyntaxError if you like.  You can also keep your "extra" 
sys.PS2 line if you like.

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