134918 2014-07-14 23:03:05 -0700 DRT/WTR should clear the memory cache between tests 2015-08-05 10:33:01 -0700 1 1 1 Unclassified WebKit Tools / Tests 528+ (Nightly build) Unspecified Unspecified NEW P2 Normal --- 1 simon.fraser koivisto ap cdumez dino kling koivisto simon.fraser oldest_to_newest 1022414 0 simon.fraser 2014-07-14 23:03:05 -0700 DRT doesn't seem to clear the memory cache between tests. I was trying to make a test that has window.internals.settings.setImageSubsamplingEnabled(true); and a ref test that does not, but the CachedImage was created by the test then just re-used by the reference, giving me a bogus pass. 1115016 1 simon.fraser 2015-08-05 09:03:28 -0700 Antti says: I think that is a too big of a hammer. You can use internals.clearMemoryCache() if your test relies on empty memory cache. 1115023 2 cdumez 2015-08-05 09:20:16 -0700 I am personally in favor of this change. I will help reduce flakiness. I had to add internals.clearMemoryCache() calls at the beginning of 24 tests recently to make them not flaky, I don't think this is very scalable. We already disable PageCache during testing, I think it makes sense to make the MemoryCache opt-in as well. 1115024 3 cdumez 2015-08-05 09:21:49 -0700 (In reply to comment #2) > I am personally in favor of this change. I will help reduce flakiness. I had > to add internals.clearMemoryCache() calls at the beginning of 24 tests > recently to make them not flaky, I don't think this is very scalable. We > already disable PageCache during testing, I think it makes sense to make the > MemoryCache opt-in as well. I would also add that I wasted engineering time investigating the source of the flakiness until I was able to determine the reason was the memory cache. This WILL happen again and more people WILL waste time on this. 1115030 4 simon.fraser 2015-08-05 09:31:35 -0700 Reopening. 1115032 5 ap 2015-08-05 09:38:12 -0700 One concern if that *may* make the tests substantially slower. We'll need to measure performance if we do this. 1115047 6 koivisto 2015-08-05 10:33:01 -0700 internals.clearMemoryCache is not to meant to be flakiness fix but used when a test actually relies on having a clear cache. Doing it everywhere would slow down tests (no idea if enough to matter) and reduce implicit test coverage, moving testing further from real browser behavior in general.