Advancing Gamepad API Test Automation

[xingri]

1. Motivation

The Gamepad API is essential for enabling game controllers and other input devices to interact with web applications, making it a critical component for gaming and immersive experiences on the web. However, the lack of automated test coverage currently limits consistent behavior across browsers. Comprehensive automated testing for the Gamepad API is key to ensuring interoperability, improving reliability, and increasing developer confidence.
In 2025, this effort was scoped as an investigation rather than a focus area due to the lack of automated test coverage, which is essential for scoring interoperability improvements. The rationale is outlined here.
We propose to continue the Gamepad API as an investigation effort for Interop 2026, building on the foundational work completed during the 2025 cycle.

2. Impact

• Cross-browser consistency: Addresses known inconsistencies in Chrome, Safari, Firefox, and Edge.
• Developer benefit: Improves reliability for gaming and XR applications, reducing fragmentation.
• Future readiness: Establishes the foundation for the Gamepad API to become a scored focus area in future Interop cycles.

3. Progress in 2025

• Refined the manual test API to better reflect real-world usage scenarios and Identified key gaps and inconsistencies in browser behavior: Interop 2025 - Gamepad API testing
• Defined interfaces for automation, laying the groundwork for future automated testing: Gamepad API testing, Integrate with WebDriver and WebDriver BiDi for automation w3c/gamepad#224

However, automated test implementations have not yet been completed, and the current coverage is still insufficient to support scoring via pass rates.

4. Proposal for 2026

We propose to continue this as an investigation effort with the following goals:

• Implement the automation interfaces defined in 2025.
• Develop initial automated tests for core Gamepad API functionality.
• Validate test behavior across major browsers.
• Identify and document remaining spec ambiguities or implementation inconsistencies.

This continued effort will help bring the Gamepad API closer to qualifying as a focus area in future Interop cycles.

5. Risks

• Complexity of automation: Requires coordination across multiple engines to ensure consistent behavior.
• Spec ambiguities: May uncover unresolved issues that need W3C discussion, but these will be documented rather than resolved within Interop.

6. Timeline

• Q1–Q2 2026: WebKit & Chromium Implement automation interfaces and create initial automated tests.
• Q3 2026: Validate tests across major browsers; refine based on feedback.
• Q4 2026: Document remaining gaps and ambiguities; prepare for potential future focus area proposal.

7. Collaborators

• Webkit: @marcoscaceres
• Chromium: @nondebug
• NVIDIA: @xingri

[nairnandu]

Thank you @xingri for creating this proposal! Since this is a carryover proposal, I have labelled it accordingly.

[xingri]

That's right. Thank you for the labelling @nairnandu .