The roles-computedRoleString.html layout test contains a large number of test cases, but no way to enable/disable an individual test case. Thus when there's a regression in just one specific element, gardeners wind up adding the test as a complete failure to TestExpectations and thus none of those tests get run on the affected platform. See, for example, bug 163383.
Given the importance of this particular layout test, and a lack of developer resources, we need a better solution. What is already being done for roles-exposed.html, namely adding a "data-platform" attribute to each element, would make it possible to enable/disable individual test cases for a given platform while allowing that platform to benefit from the remainder of the test.
Created attachment 331646 [details]
Chris: Any objections?
Comment on attachment 331646 [details]
Clearing flags on attachment: 331646
Committed r227158: <https://trac.webkit.org/changeset/227158>
All reviewed patches have been landed. Closing bug.
Another approach would be to split the test into multiple files, and use the normal TestExpectations mechanism.