Software quality assurance#

The following section includes information about the WNTR software repository, software tests, documentation, examples, bug reports, feature requests, and ways to contribute. Developers should follow the Developer instructions to clone and setup WNTR.

GitHub repository#

WNTR is maintained in a version controlled repository. WNTR is hosted on US EPA GitHub organization at USEPA/WNTR.

Software tests#

WNTR includes continuous integration software tests that are run using GitHub Actions. Travis CI and AppVeyor are used by the core development team as secondary testing services. The tests are run each time changes are made to the repository. The tests cover a wide range of unit and integration tests designed to ensure that the code is performing as expected. New tests are developed each time new functionality is added to the code. Testing status (passed/failed) and code coverage statistics are posted on the README section at USEPA/WNTR.

Tests can also be run locally using the Python package pytest. For more information on pytest, see The pytest package comes with a command line software tool. Tests can be run in the WNTR directory using the following command in a command line/PowerShell prompt:

pytest wntr

In addition to the publicly available software tests run using GitHub Actions, WNTR is also tested on private servers using several large water utility network models.


WNTR includes a user manual that is built using the Read the Docs service. The user manual is automatically rebuilt each time changes are made to the code. The documentation is publicly available at The user manual includes an overview, installation instructions, simple examples, and information on the code structure and functions. WNTR includes documentation on the API for all public functions, methods, and classes. New content is marked Draft. Python documentation string formatting can be found at

To build the documentation locally, run the following command in a command line/PowerShell prompt from the documentation directory:

make html

HTML files are created in the documentation/_build/html directory. Open index.html to view the documentation.


WNTR includes examples to help new users get started. These examples are intended to demonstrate high level features and use cases for WNTR. The examples are tested to ensure they stay current with the software project.

Bug reports and feature requests#

Bug reports and feature requests can be submitted to USEPA/WNTR#issues. The core development team will prioritize and assign bug reports and feature requests to team members.


Software developers, within the core development team and external collaborators, are expected to follow standard practices to document and test new code. Software developers interested in contributing to the project are encouraged to create a Fork of the project and submit a Pull Request using GitHub. Pull requests will be reviewed by the core development team.

Pull requests can be made to the main or dev (development) branch. Developers can discuss new features and the appropriate branch for contributing by opening a new issue on USEPA/WNTR#issues.

Pull requests must meet the following minimum requirements to be included in WNTR:

  • Code is expected to be documented using Read the Docs.

  • Code is expected have sufficient tests. Sufficient is judged by the strength of the test and code coverage. An 80% code coverage is recommended.

  • Large files (> 1Mb) will not be committed to the repository without prior approval.

  • Network model files will not be duplicated in the repository. Network files are stored in examples/network and wntr/tests/networks_for_testing only.

Development team#

WNTR was developed as part of a collaboration between the United States Environmental Protection Agency Office of Research and Development, Sandia National Laboratories, and Purdue University. See USEPA/WNTR for a full list of contributors.