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

Testing software is 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.


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;
for example, a Docker container, to minimise the risk of damaging
your system.


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

  • You have installed Python 3.8 or 3.9 (we have not yet tested with Python 3.10, there might
    be some problems due to changed internals regarding the byte-code instrumentation).
  • 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 the same as the Python 3.8 interpreted or a
virtual environment that uses Python 3.8 as its interpreter, 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 \
  --algorithm WHOLE_SUITE \
  --project_path /tmp/foo \
  --output_path /tmp/testgen \

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 poetry shell to switch to the virtual environment in your current shell

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

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

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. Find the location of the virtual environment by running poetry env info in the project directory.
  3. Go to Settings / Project: pynguin / Project interpreter
  4. Add and use a new interpreter that points to the path of the virtual environment
  5. Set the default test runner to pytest