Use Tox as the runner#
Tox is a great tool for testing against multiple Python versions or dependency sets.
You can configure a
tox.ini like the following to integrate your testing with PDM:
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To use the virtualenv created by Tox, you should make sure you have set
pdm config use_venv true. PDM then will install
pdm.lock into the virtualenv. In the dedicated venv you can directly run tools by
pytest tests/ instead
pdm run pytest tests/.
You should also make sure you don't run
pdm add/pdm remove/pdm update/pdm lock in the test commands, otherwise the
file will be modified unexpectedly. Additional dependencies can be supplied with the
deps config. Besides,
config should be set as the above example to make PDM work properly.
To get rid of these constraints, there is a Tox plugin tox-pdm which can ease the usage. You can install it by
And you can make the
tox.ini much tidier as following, :
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See the project's README for a detailed guidance.
Use Nox as the runner#
Nox is another great tool for automated testing. Unlike tox, Nox uses a standard Python file for configuration.
It is much easier to use PDM in Nox, here is an example of
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PDM_IGNORE_SAVED_PYTHON should be set so that PDM can pick up the Python in the virtualenv correctly. Also make sure
pdm is available in the
Before running nox, you should also
pdm config use_venv true to enable venv reusing.
About PEP 582
By default, if you run tools by
__pypackages__ will be seen by the program and all subprocesses created by it. This means virtual environments created by those tools are also aware of the packages inside
__pypackages__, which result in unexpected behavior in some cases.
nox, you can avoid this by adding a line in
PYTHONPATH will not be passed to the test sessions so this isn't going to be a problem. Moreover, it is recommended to make
tox live in their own pipx environments so you don't need to install for every project. In this case, PEP 582 packages will not be a problem either.
Use PDM in Continuous Integration#
Only one thing to keep in mind -- PDM can't be installed on Python < 3.7, so if your project is to be tested on those Python versions, you have to make sure PDM is installed on the correct Python version, which can be different from the target Python version the particular job/task is run on.
Fortunately, if you are using GitHub Action, there is pdm-project/setup-pdm to make this process easier. Here is an example workflow of GitHub Actions, while you can adapt it for other CI platforms.
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For GitHub Action users, there is a known compatibility issue on Ubuntu virtual environment.
If PDM parallel install is failed on that machine you should either set
false or set env
It is already handled by the
If your CI scripts run without a proper user set, you might get permission errors when PDM tries to create its cache directory. To work around this, you can set the HOME environment variable yourself, to a writable directory, for example:
Use other PEP 517 backends#
PDM supports ALL PEP 517 build backends that comply with PEP 621 specification. At the time of writing,
flit is going to switch to PEP 621 metadata in the near future, then you can keep
flit as the build-backend while still managing dependencies using PDM:
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PDM will call the correct backend when
Use PDM in a multi-stage Dockerfile#
It is possible to use PDM in a multi-stage Dockerfile to first install the project and dependencies into
and then copy this folder into the final stage, adding it to
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Integrate with other IDE or editors#
Work with lsp-python-ms in Emacs#
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