The following is an attempt to provide a historical view and update on the current status of work on our MSE CR test suite.
FTR the best historical record I can find of 2015 work on the MSE test suite is in:
https://lists.w3.org/Archives/Public/public-html-media/2015Oct/0084.html
Yosuke did an initial analysis of existing MSE test suite coverage in January 2016. See:
https://lists.w3.org/Archives/Public/public-html-media/2016Jan/0005.html
https://docs.google.com/spreadsheets/d/1uvIAPLfQ51OnMhxzPt3eEDy5eVyPpRHeNPnycE7kp1c/edit?usp=sharing
Yosuke also produced a comparison of the WPT tests and the Blink tests he had found in Feb 2016:
https://lists.w3.org/Archives/Public/public-html-media/2016Feb/0008.html
http://www.w3.org/2016/02/MSE-WPT-Blink-dir-comparison.pdf
Unfortunately Yosuke has not been able to continue this work and I understand that Philippe is now going to help here.
After working on the matter thru Feb and Mar, Matt informed us that he had obtained permission to submit the additional Blink MSE tests on Apr 5. BTW, on April 7 Yosuke offered to share this news with the WG but I cannot find any evidence that he did this.
Matt submitted one of the Blink MSE test cases to Web Platform Tests on April 25:
https://github.com/w3c/web-platform-tests/pull/2896
And on May 3 Matt indicated that more PRs were on his to do list:
* Preparing and submitting web-platform-test merge batches from Chromium MSE test suite
Philippe: How will you be able to help with extending the MSE test suite coverage?
Matt: Are you still planning to submit more of the Blink tests to WPT?
/paulc
HME WG Chair