doctest environment question

[thomas.guest at gmail.com]

I'm not making progress with the following and would appreciate any
help.

Here's an interpreted Python session.

>>> import sys
>>> def f(): pass
...
>>> this_module = sys.modules[__name__]
>>> delattr(this_module, 'f')
>>> f()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'f' is not defined

Suppose I want to doctest this behaviour. I cut and paste the above
into a file "test.txt" then run:

python -c "import doctest; doctest.testfile('test.txt')"

This gives me unexpected test failures:

python -c "import doctest; doctest.testfile('test.txt')"
**********************************************************************
File "test.txt", line 5, in test.txt
Failed example:
    delattr(this_module, 'f')
Exception raised:
    Traceback (most recent call last):
      File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/doctest.py", line 1212, in __run
        compileflags, 1) in test.globs
      File "<doctest test.txt[3]>", line 1, in <module>
        delattr(this_module, 'f')
    AttributeError: f
**********************************************************************
File "test.txt", line 6, in test.txt
Failed example:
    f()
Expected:
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    NameError: name 'f' is not defined
Got nothing
**********************************************************************
1 items had failures:
   2 of   5 in test.txt
***Test Failed*** 2 failures.