organizing python code with tests

[Alex Marandon]

eliben wrote:
> Hello,
> 
> At the moment, I place all the code of my project in a src/ directory,
> and all the tests in a sibling tests/ directory, so for instance a
> sample project can look like this:
> 
> doc/
>   ...
> src/
>   play.py
>   write.py
> tests/
>   test_play.py
>   test_write.py
> 
> While this works fine, I have a couple of questions:
> 
> 1) To make this scheme work, each test file begins with
> sys.path.insert(0, '../src'). I wonder if there's a better way to do
> this, because this one doesn't look flexible (what if the code gets
> complex and I subdivide it to directories in src/...)

You would then make packages and access your modules within tests using 
Python dot notation. In this case though, you'll probably want to rename 
src into a more specific package name.

If you don't want to mess up with the python path within each test file, 
you may want to make the package your testing available globally for
import. A quick way to do it is by setting the PYTHONPATH environment 
variable. This can quickly become tedious if you work on multiple 
packages. Another solution would be to link your packages within 
site-packages, which is (hopefully ;) already in your path. The ultimate 
solution to do that is to make you package an egg and install it in 
development mode (ie: python setup.py develop). This is made very easy 
by Paste Script and its basic_package template (paster create -t 
basic_package), see http://pythonpaste.org/script/developer.html for 
more on that. A good thing with having your package in your Python path 
is that you can fire a interactive interpreter from anywhere and play 
with your API.

> 2) Is there a better way to organize this ? Preferably I'm looking for
> a single method that is applicable to:
>   * Complete stand-alone applications with a single entry-point
>   * Libraries with several files that should be imported by the users

Does it actually make a difference when it comes to unit testing? Even 
for standalone apps you'll want to unit test each module composing the 
app, won't you ? ;-)