Skip Gambit Notebook Tests Locally By Default? A Discussion

Introduction: Addressing Local Notebook Testing Challenges in Gambit

The core question we're tackling is: should Gambit notebook tests be skipped locally by default? This stems from recent experiences and discussions within the Gambit project, particularly concerning the complexities introduced by the OpenSpiel notebook. The primary challenge revolves around external dependencies. To run these tests locally, developers need to have both open_spiel and matplotlib installed, creating a barrier for contributors and potentially slowing down local development workflows. This in-depth exploration delves into the rationale behind this suggestion, the issues it aims to resolve, and the potential implications for the Gambit project's testing strategy. We will explore the current state of notebook testing, the problems encountered, and a proposed solution to enhance the developer experience while maintaining test coverage integrity. This analysis will cover the technical aspects, the practical implications for developers, and the broader impact on the project's continuous integration and testing pipelines. By understanding the nuances of this issue, we can collectively decide on the best path forward for Gambit's notebook testing practices. The goal is to strike a balance between thorough testing and a streamlined development process, ensuring that Gambit remains robust and accessible to contributors. This discussion also opens the door to re-evaluate our reliance on local testing versus continuous integration (CI) systems for specific types of tests, particularly those with external dependencies. Ultimately, our aim is to create a more efficient and user-friendly environment for Gambit development, fostering contributions and maintaining high-quality code.

The Problem: External Dependencies and Local Testing Awkwardness

Currently, running Gambit notebook tests locally can be a bit of a hurdle, especially with the introduction of the OpenSpiel notebook. The main issue is the need for external dependencies like open_spiel and matplotlib. If a developer doesn't have these libraries installed, the tests will fail, creating friction in the development process. This local testing awkwardness can discourage developers from running tests frequently, potentially leading to unnoticed issues and a slower feedback loop. The requirement to install these dependencies locally adds an extra step to the setup process for new contributors and can be a deterrent for quick iterations and experimentation. Furthermore, maintaining these dependencies can be a challenge, as different versions might lead to inconsistencies between local test runs and those in the continuous integration (CI) environment. This discrepancy can create confusion and make it difficult to diagnose issues effectively. The need for a consistent and reliable testing environment is paramount, and the current setup doesn't always provide that for notebook tests. Therefore, rethinking our approach to local notebook testing is crucial to ensure a smoother and more efficient development experience for everyone involved in the Gambit project. By addressing these challenges, we can foster a more collaborative and productive environment, encouraging developers to contribute and maintain high-quality code.

Proposed Solution: Skip Notebook Tests Locally by Default

The suggestion on the table is a straightforward yet potentially impactful one: skip running Gambit's notebook tests locally by default. This means that when a developer runs the standard test suite, the notebook tests would not be executed unless a specific flag or switch is provided to the pytest command. The rationale behind this proposal is to alleviate the dependency burden on local development environments. By default, developers wouldn't need to have open_spiel or matplotlib installed just to run a basic test cycle. This would streamline the development workflow, especially for those working on non-notebook-related code. The primary reliance for notebook testing would then shift to the GitHub Actions continuous integration (CI) environment, where these dependencies are managed and consistently available. This approach leverages the strengths of CI systems, ensuring that notebook tests are executed in a controlled and reproducible environment. Developers could still run notebook tests locally when needed, but it would be a deliberate action, signaling their intent to specifically test notebook functionality. This opt-in approach provides flexibility while minimizing the friction associated with local dependency management. By adopting this strategy, we aim to improve the developer experience, reduce setup complexity, and maintain the integrity of our testing process. This change would allow developers to focus on their specific tasks without being bogged down by unnecessary dependencies, ultimately contributing to a more efficient and enjoyable development experience.

Benefits of Skipping Local Notebook Tests by Default

There are several compelling benefits to adopting the proposed solution of skipping notebook tests locally by default. First and foremost, it significantly reduces the barrier to entry for new contributors. By removing the need to install open_spiel and matplotlib for basic testing, developers can quickly get started with the project without encountering dependency-related hurdles. This reduced barrier can lead to increased participation and a more vibrant community. Secondly, it streamlines the development workflow for those working on non-notebook-related code. Developers can run the core test suite without the overhead of notebook tests, resulting in faster test cycles and a more responsive development experience. This efficiency gain can translate to quicker iterations and faster progress on features and bug fixes. Thirdly, it promotes a more consistent testing environment by relying on GitHub Actions for notebook testing. CI systems provide a controlled and reproducible environment, ensuring that tests are executed under the same conditions every time. This consistency reduces the likelihood of false positives or negatives due to environmental differences between local machines. Furthermore, this approach aligns with the best practices of continuous integration, where automated testing is a cornerstone of the development pipeline. By centralizing notebook testing in the CI environment, we can ensure that these tests are run regularly and reliably, providing a safety net for code changes. Finally, it allows developers to focus their local environment setup on the specific tasks they are working on. If a developer is working on a notebook feature, they can choose to install the necessary dependencies and run the notebook tests. However, if they are working on other parts of the codebase, they can avoid the overhead of these dependencies. This flexibility allows for a more tailored and efficient development experience.

Addressing the OpenSpiel Notebook Warning

In addition to the core issue of local notebook testing, there's also a warning generated by the OpenSpiel notebook that needs attention. The warning message, as quoted in the original discussion, highlights a missing id field in notebook cells, which will become a hard error in future versions of nbformat. This OpenSpiel notebook warning indicates a potential compatibility issue with newer versions of the nbformat library, which is used for reading and writing Jupyter Notebook files. Addressing this warning is crucial to ensure the long-term maintainability and compatibility of the Gambit project's notebooks. Ignoring this warning could lead to test failures or unexpected behavior in the future. The suggested solution in the warning message itself is to use the normalize() function on the notebooks before validation. This function, available since nbformat 5.1.4, automatically adds the missing id fields to the notebook cells. Applying this normalization step would resolve the warning and ensure that the notebooks are compatible with future versions of nbformat. This could be implemented as a pre-commit hook or as part of the CI pipeline to automatically normalize notebooks before they are committed to the repository. Alternatively, a script could be run to normalize all existing notebooks in the repository. Addressing this warning proactively demonstrates a commitment to code quality and long-term maintainability. It also prevents potential issues from arising in the future, saving time and effort in debugging and fixing compatibility problems. By resolving this warning, we can ensure that the Gambit project's notebooks remain a valuable and reliable resource for users and developers alike.

Alternative Solutions and Considerations

While skipping notebook tests locally by default offers a compelling solution, it's crucial to consider alternative approaches and potential drawbacks. One alternative is to use a virtual environment management tool like conda or venv to isolate the dependencies required for notebook testing. This would allow developers to easily create separate environments with the necessary dependencies, avoiding conflicts with their global Python installation. However, this approach still requires developers to be aware of the dependencies and to set up the virtual environment correctly, which can be an additional step for new contributors. Another consideration is the potential impact on test coverage. If notebook tests are only run in CI, there's a risk that local development changes might introduce issues that are not caught until the code is pushed to the repository. To mitigate this risk, it's important to encourage developers to run notebook tests locally when they are working on notebook-related features. This could be achieved through clear documentation and guidance, as well as providing convenient ways to run the tests, such as a dedicated command or script. Furthermore, we could explore the possibility of using Docker containers to create a consistent testing environment for both local and CI runs. Docker containers encapsulate all the necessary dependencies and configurations, ensuring that tests are executed in the same environment regardless of the host machine. This approach can provide a high degree of consistency and reproducibility, but it also adds complexity to the development workflow. Ultimately, the best solution will depend on the specific needs and priorities of the Gambit project. It's important to weigh the benefits and drawbacks of each approach carefully and to choose the solution that best balances developer convenience, test coverage, and maintainability. A collaborative discussion involving the Gambit community is essential to make an informed decision.

Conclusion: Striking a Balance for Gambit's Testing Strategy

The discussion surrounding whether to skip Gambit notebook tests locally by default highlights the ongoing need to balance developer convenience with thorough testing. The proposed solution offers a pragmatic approach to address the challenges posed by external dependencies, particularly with the introduction of the OpenSpiel notebook. By shifting the primary responsibility for notebook testing to the GitHub Actions CI environment, we can streamline the local development workflow and reduce the barrier to entry for new contributors. However, it's crucial to acknowledge the potential drawbacks and to implement safeguards to maintain test coverage. Encouraging developers to run notebook tests locally when working on notebook-related features, providing clear documentation and guidance, and exploring alternative solutions like Docker containers are all important considerations. Addressing the OpenSpiel notebook warning regarding the missing id field is also essential for ensuring long-term compatibility and maintainability. Ultimately, the goal is to create a testing strategy that is both effective and efficient, providing a safety net for code changes while minimizing friction for developers. This requires a collaborative approach, involving the Gambit community in the decision-making process and continuously evaluating the effectiveness of our testing practices. By striking the right balance, we can ensure that Gambit remains a robust and accessible project, fostering contributions and maintaining high-quality code. Further research into best practices for testing notebooks in a CI/CD environment and exploring tools that can automate the normalization of notebooks would be beneficial. For additional information on continuous integration and testing, you can visit reputable resources such as Jenkins.