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Pynguin is a tool for automated unit test generation for Python

Project description


Pynguin (IPA: ˈpɪŋɡuiːn), the PYthoN General UnIt test geNerator, is a tool that allows developers to generate unit tests automatically.

Testing software is often considered to be a tedious task. Thus, automated generation techniques have been proposed and mature tools exist—for statically typed languages, such as Java. There is, however, no fully-automated tool available that produces unit tests for general-purpose programs in a dynamically typed language. Pynguin is, to the best of our knowledge, the first tool that fills this gap and allows the automated generation of unit tests for Python programs.

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License MIT Code style: black Ruff PyPI version Supported Python Versions Documentation Status DOI REUSE status Downloads SWH

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Please Note:

Pynguin executes the module under test! As a consequence, depending on what code is in that module, running Pynguin can cause serious harm to your computer, for example, wipe your entire hard disk! We recommend running Pynguin in an isolated environment; use, for example, a Docker container to minimize the risk of damaging your system.

Pynguin is only a research prototype! It is not tailored towards production use whatsoever. However, we would love to see Pynguin in a production-ready stage at some point; please report your experiences in using Pynguin to us.


Before you begin, ensure you have met the following requirements:

  • You have installed Python 3.10 (we have not yet tested with Python 3.11, there might be some problems due to changed internals regarding the byte-code instrumentation).

    Attention: Pynguin now requires Python 3.10! Older versions are no longer supported!

  • You have a recent Linux/macOS/Windows machine.

Please consider reading the online documentation to start your Pynguin adventure.

Installing Pynguin

Pynguin can be easily installed using the pip tool by typing:

pip install pynguin

Make sure that your version of pip is that of a supported Python version, as any older version is not supported by Pynguin!

Using Pynguin

Before you continue, please read the quick start guide

Pynguin is a command-line application. Once you installed it to a virtual environment, you can invoke the tool by typing pynguin inside this virtual environment. Pynguin will then print a list of its command-line parameters.

A minimal full command line to invoke Pynguin could be the following, where we assume that a project foo is located in /tmp/foo, we want to store Pynguin's generated tests in /tmp/testgen, and we want to generate tests using a whole-suite approach for the module (wrapped for better readability):

pynguin \
  --project-path /tmp/foo \
  --output-path /tmp/testgen \

Please find a more detailed example in the quick start guide.

Contributing to Pynguin

For the development of Pynguin you will need the poetry dependency management and packaging tool. To start developing, follow these steps:

  1. Clone the repository

  2. Change to the pynguin folder: cd pynguin

  3. Create a virtual environment and install dependencies using poetry: poetry install

  4. Make your changes

  5. Run make check to verify that your changes pass all checks

    Please see the poetry documentation for more information on this tool.


Pynguin is developed at the Chair of Software Engineering II of the University of Passau.

Maintainer: Stephan Lukasczyk


Development using PyCharm.

If you want to use the PyCharm IDE you have to set up a few things:

  1. Import pynguin into PyCharm.
  2. Let PyCharm configure configure a virtual environment using poetry.
  3. Set the default test runner to pytest
  4. Set the DocString format to Google


This project is licensed under the terms of the MIT License. Pynguin was using the GNU Lesser General Public License (LGPL) until version 0.29.0, its licence was changed with version 0.30.0.

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