Suggestion: remove tests from the distribution

[vfilimonov]

Would it make sense to remove tests folder from the pandas distribution? It takes roughly 33% of the whole package weight.

It is especially important when using pandas inside the AWS Lambdas, where the deployment package size is limited to 50 MB zipped and 5 MB might really make a difference.

# Uncompressed
du -h -s pandas*
 46.5M	pandas
 30.9M	pandas_no_tests

# Compressed
du -h -s pandas*
 14.7M	pandas.zip
 10.1M	pandas_no_tests.zip

[TomAugspurger]

I think we've talked about that in the past. We do have pandas.test() as part of the public API however, so we'd need to consider that.

A couple options:

1. Provide a separate distribution like pandas-slim or something that excludes these files (and docs)
2. Have pandas.test() fetch the source files on demand. That seems a bit messy though.

Just as a note: we do exclude the test data files that are present in the git repository. So we're only talking about source files.

[vfilimonov]

Hello @TomAugspurger

pandas-slim sounds like an good workaround.

It looks like docs are not a part of the distribution.
And right it's tests code only without the data files - in terms of size they are second to _libs and almost equal to the rest of the code.

8.0K	./arrays
 16K	./errors
 24K	./api
 40K	./__pycache__
 76K	./compat
 88K	./_config
248K	./tseries
308K	./util
440K	./plotting
2.3M	./io
6.7M	./core
 17M	./tests
 20M	./_libs

And what is the reason of having tests as a part of an API? I see that numpy, scipy, matplotlib etc are doing the same (while many other libs, especially web-oriented like flask, requests, jinja don't)?

[TomAugspurger]

Thanks for correcting me on the docs stuff. I'm not sure why all these projects tend to include tests. As a guess, I suspect that we have more issues related to how the packages are built (compilers, flags, libraries we link to) than they do.

…

On Mon, Jan 6, 2020 at 1:56 PM Vladimir Filimonov ***@***.***> wrote: Hello @TomAugspurger <https://github.com/TomAugspurger> pandas-slim sounds like an good workaround. It looks like docs are not a part of the distribution. And right it's tests code only without the data files - in terms of size they are second to _libs and almost equal to the rest of the code. 8.0K ./arrays 16K ./errors 24K ./api 40K ./__pycache__ 76K ./compat 88K ./_config 248K ./tseries 308K ./util 440K ./plotting 2.3M ./io 6.7M ./core 17M ./tests 20M ./_libs And what is the reason of having tests as a part of an API? I see that numpy, scipy, matplotlib etc are doing the same (while many other libs, especially web-oriented like flask, requests, jinja don't)? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#30741?email_source=notifications&email_token=AAKAOIUZLK4U3RLNROXYKADQ4OEHPA5CNFSM4KDF2MLKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEIGS7KI#issuecomment-571289513>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAKAOIR5SCPXJ5N7HFOBDRDQ4OEHPANCNFSM4KDF2MLA> .

[stonecharioteer]

I particularly used to run the tests for numpy, scikitlearn and matplotlib after installing, since at times I'd have them fail on Windows. However this was quite some time ago, 4 years ago perhaps. Perhaps other users were doing the same?

[jonringer]

I'm a package manager for nixpkgs, and I'm against removing tests from the sdist package, however, removing from the wheel would make sense from a packaging standpoint. It's considered best practice in FOSS that if you distribute source, you also distribute tests along side it.

EDIT:
tests are a nice guarantee that the package is working as intended.

We could also checkout the github repo for tests. However, quickly looking at the setup.py, pandas was meant to have the CI set correct metadata such as version. So the version-controlled source can't be directly be used to package pandas.

[joaoe]

Hi. i reported this elsewhere, so I'm pasting my comment here.

My use case
After a pip install pandas the lib/site-packages/pandas/tests/ includes a lot of testing code which is definitely not relevant for me and many other end users of pandas.
This bloats the installation and makes installation slower.
I'm working on packaging a python environment to distribute with a preinstalled set of modules and application and there are too many popular 3rd-party modules which include unneeded test code, like numpy, IPython, jupyterlab, etc, which needs to be striped to keep the package size down. I'll be reporting issues to these projects as well.

Suggestion
Therefore, my suggestion is to keep the pandas module streamlined, and move the tests out. Perhaps create a pandas-unittests module if people are interested in it, or just expect users to checkout the code. Another possibility would be to skip packaging the tests folder and conftest.py when creating packages to upload to pypi.org.

Regarding pandas-slim, everyone and their mothers have a dependency on pandas which would pull the whole code again with tests.

It's considered best practice in FOSS that if you distribute source, you also distribute tests along side it.

That perfectly fine. The discussion is whether tests are bundled with the pandas module or not.

Since you are now almost releasing 1.0 it might be a bit short notice to include this is such a big release. But for the next major release, it could work.

Thank you very much for your attention.

[vfilimonov]

A small remark: as a part of recent commit to pyarrow @wesm removed pyarrow.tests from the wheel which to my understanding contributed 2.3 MB of ~60 MB installed size.

In case of pandas tests folder contributed (as of version 1.0.3) tests folder contributed 17.9 MB out of 49 MB installed size.

So I'd like to bring the question back to the discussion and perhaps, @wesm could comment on that?

[wesm]

I think it would be a good idea to not ship the tests in wheels. If you want users to be able to run the tests against their production installs perhaps the tests can be packaged as a separate source wheel. Install size is becoming a problem because of size constraints in things like AWS Lambda.

[TomAugspurger]

https://uwekorn.com/2020/10/28/trimming-down-pyarrow-conda-2-of-x.html has some information.

I think I've come around to the idea that we can just not ship the test files in the main pandas distributions. We can have a separate pandas-tests so that pip install pandas-tests package that's just

1. The test files
2. A small __init__.py file ties things together

We could even update pandas.test() to check for the presence of the pandas-tests package.