or, Adventures in Yak Shaving
I started working on a python package that I might eventually want to publish. I
consulted the PyPI documentation to make sure I set up the directory structure
correctly, and along the way I encountered a mention
of pip install -e, the command that lets you install packages in the works in
editable form. (To your virtualenv, of course.)
"Neat," I think, "but that looks like a lot of setup. I would
have to add configuration files and whatnot to get this to be recognized as a
package. I'll leave that for later."
After a little bit of code, I decide to write some tests with pytest.
It's a great way to make sure my code is doing what I expect, and unlike my old
practice of tinkering in an interpreter, writing pytest functions saves my test
for later so that I'm alerted if they ever break. The more I use it, the more I
find myself wondering, "Why didn't I start using this sooner?" The only wrinkle
has to do with my directory structure:
/path/to/package/
package/
__init__.py
...
test/
test_1.py
test_2.py
...
files_for_testing/
...
The scripts all have relative paths pointing to the test files, so I run
pytest inside the test directory. This means my package is not in python's
path when I run it. Up to now, I've been adding the project directory to the
PYTHONPATH environment variable in the shell, but I've been looking for a way to
do that more pythonically. "Why not have the test scripts add to sys.path?" I
muse.
Of course, having had internet access for decades now, I recall details with the
consistency of a butterfly, and so I turn to google to find out where in
sys.path to insert the relevant directory. In doing so, I find
an overly detailed discussion on stack exchange
where user agf helpfully chides:
you need to be using virtualenv ....
That's why people consider insert(0, to be wrong -- it's an incomplete, stopgap solution to the problem of managing multiple environments.
So now I guess I might as well get back to shaving the yak and set up my package
for pip. I was trying to avoid the extraneous work to focus on the main
project, but it turns out that I might as well do some of it. It should save me
time in the future, right? I think that's how it's supposed to work.
Or maybe I'll just wind up like poor Hal:
