birds. migration

Migrating Private Tests to the Commons

Moving tests to a public location for the benefit of all

The Chromium team wrote a large set of valuable tests for a new web standard. We wanted to move them to a place where more people could use and improve them.


Google had accumulated close to 100 tests for the developing Service Workers standard. They were authored to run within the Chromiuminfrastructure (Chromium is the project behind Google Chrome, and this prevented other browser implementers from using them and helping to maintain them. It also increased the risk for incompatibilities.


We worked to transfer these tests to the Web Platform Tests project, where they would be consumed and maintained by many browser makers. This involved code re-formatting, verification of specification compliance, removal of non-standard code, and general improvements to coverage/thoroughness. Throughout this process, we took special care to preserve test coverage within the Chromium project.


In addition to improving the Web Platform Tests project by sharing Chromium’s tests, we identified implementation bugs in both Chromium and Firefox. We also reported issues with the Service Workers specification itself and submitted patches for various editorial problems.

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