[Tutor] [newbie] import error after restart (virtualenv)

[Peter Otten]

David wrote:

> Dear Tutors,
> 
> I am reading through Harry Percival's "Test-Driven Development with
> Python".
> 
> As I finished chapter 3 yesterday, I was fully on track, perfectly
> aligned with the book.
> 
> Today I restarted my computer, activated the virtualenv in question --
> and get an error message that was not there beforehand:
> 
> 
(Percival_TDD)david at lubuntu:~/PycharmProjects/Percival_TDD/superlists/lists$
> python tests.py
> Traceback (most recent call last):
>   File "tests.py", line 5, in <module>
>     from lists.views import home_page
> ImportError: No module named 'lists'
> 
> 
> I neither understand why he doesn't find 'lists' anymore nor do I know
> how to solve the problem. Nothing seems to have changed in the meantime...
> 
> Can you please guide me towards a solution?
> 
> Thank you!
> 
> David
> 
> 
> 
> The project structure looks as follows:
> 
> (Percival_TDD)david at lubuntu:~/PycharmProjects/Percival_TDD/superlists$
> tree .
> ├── db.sqlite3
> ├── functional_tests.py
> ├── lists
> │   ├── admin.py
> │   ├── __init__.py
> │   ├── migrations
> │   │   └── __init__.py
> │   ├── models.py
> │   ├── tests.py
> │   └── views.py
> ├── manage.py
> └── superlists
>     ├── __init__.py
>     ├── __pycache__
>     │   ├── __init__.cpython-34.pyc
>     │   ├── settings.cpython-34.pyc
>     │   ├── urls.cpython-34.pyc
>     │   └── wsgi.cpython-34.pyc
>     ├── settings.py
>     ├── urls.py
>     └── wsgi.py

Given this layout you have to ensure that the parent folder of lists is in 
sys.path. This can be achieved by setting the PYTHONPATH variable for just 
this invocation

$ PYTHONPATH=.. python tests.py

or in a more permanent way and preferably with absolute paths.

However, are you sure you ran tests.py explicitly? I've only had a cursory 
look at django and no project handy to check, but if I remember correctly

$ ./manage.py test

should take care of the details.