On Fri, 30 Oct 2020 16:04:51 GMT, Ambarish Rapte <ara...@openjdk.org> wrote:
> Each test in RegionBackgroundImageUITest makes several calls to > `robot.getPixelColor()` on App thread. Due to this each test requires more > than **60** seconds for execution. > > Fix is to save a screen capture of Scene (on App thread) and then read pixel > color from the screen capture(not on app thread). This reduces execution time > of each test to less than **3** seconds. > Ideally with this fix(commit#1) all the tests should pass. All tests do pass > on Windows and Linux but three tests fail on Mac, which used to pass without > this change. > - RegionBackgroundImageUITest.unalignedImage > - RegionBackgroundFillUITest.testScenario2 > - RegionBackgroundFillUITest.testScenario3 > > commit#2 solves the above problem. Solution is to fallback to test color > again by reading it using `robot.getPixelColor()` on App thread when a test > fails. > > One test RegionBackgroundImageUITest.unalignedImage_Cover, fails only on Mac > platform, before and after this fix. > It is reported as a new issue > [JDK-8255679](https://bugs.openjdk.java.net/browse/JDK-8255679) > > This is a test fix and affects only the tests that extend from > `RegionUITestBase` test class and does not affect other tests. > Verified that `RegionBackgroundImageUITest` and `RegionBackgroundFillUITest` > tests pass on all three platforms(except > RegionBackgroundImageUITest.unalignedImage_Cover which fails on Mac). The fact that you needed to implement a fallback to `Robot::getPixelColor` if reading a pixel from the buffer obtained by `Robot::getScreenCapture` fails (on Mac) suggests that `RegionBackgroundImageUITest` has some issues running on HiDPI displays. It also points out that there is a difference between the scaling algorithm used to read a single pixel vs an array of pixels (this might be a bug in Robot itself). I confirmed the fact that these problems are related to HiDPI scaling by running it on my Windows 10 system with 125% scaling, and I get 30 test failures. I instrumented the code and I see a couple hundred fallbacks per test even for the non-failing tests. If I force screen scale to 1 on Windows then all tests pass with no fallbacks. We used to have this problem for some of the tests in `RegionBackgroundFillUITest` as well. The fix for [JDK-8170026](https://bugs.openjdk.java.net/browse/JDK-8170026) addressed this by skipping the tests that were sensitive to screen scale (14 of them). You either need to do something similar for `RegionBackgroundImageUITest` or else fix the tests to work with different screen scales (this would be challenging). ------------- Changes requested by kcr (Lead). PR: https://git.openjdk.java.net/jfx/pull/344
