RFR: 8346581: JRadioButton/ButtonGroupFocusTest.java fails in CI on Linux

[Damon Nguyen]

On Wed, 8 Jan 2025 19:40:29 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

> **Problem:**
> 
> The `javax/swing/JRadioButton/ButtonGroupFocus/ButtonGroupFocusTest.java` test fails in CI on Linux.
> 
> The focus is on _Button 2_ instead of _Button 4_.
> 
> **Root cause:**
> 
> The additional logging revealed, an expected `KEY_PRESS` event. The test uses `Robot` API to press the <kbd>Tab</kbd> key and release it. When the test fails, there are two `KEY_PRESS` events followed by a single `KEY_RELEASE` event. Because the <kbd>Tab</kbd> key is pressed twice, the focus moves twice: from _Button 2_ (the initial state) to _Button 4_ and then back to _Button 2_.
> 
> **Fix:**
> 
> Use `CountDownLatch`es to track whether a radio button received focus. Detect the case where two `KEY_PRESS` events moved focus to _Button 2_ and report the failure.
> 
> Log focus movements and dispatched key events to facilitate failure analysis.
> 
> Take a screenshot of the test frame in case of failure.
> 
> These CI hosts seem to be quite slow, removing the delay added by `robot.setAutoDelay(100)` has reduced the number of unexpected `KEY_PRESS` events. This didn't affect Windows or macOS.

Tested this on Windows and Linux locally and on CI. Logging looks good and the test passes with repeats. LGTM

test/jdk/javax/swing/JRadioButton/ButtonGroupFocus/ButtonGroupFocusTest.java line 121:

> 119:                                                + "\n\t" + evt.getNewValue());
> 120:                         }
> 121:                     });

Suggestion:

                    evt -> System.out.println(evt.getPropertyName()
                                               + "\n\t" + evt.getOldValue()
                                               + "\n\t" + evt.getNewValue()));


Nit. Possible lambda replacement here.

test/jdk/javax/swing/JRadioButton/ButtonGroupFocus/ButtonGroupFocusTest.java line 124:

> 122: 
> 123:             // ...and dispatched key events
> 124:             Toolkit.getDefaultToolkit().addAWTEventListener(new AWTEventListener() {

The `AWTEventListener` can also be replaced with a lambda if preferred.

test/jdk/javax/swing/JRadioButton/ButtonGroupFocus/ButtonGroupFocusTest.java line 172:

> 170:             BufferedImage image = robot.createScreenCapture(getFrameBounds());
> 171:             ImageIO.write(image, "png",
> 172:                           new File("image.png"));

Does this overflow the 80 character line limit? Or is this a standard?

-------------

Marked as reviewed by dnguyen (Committer).

PR Review: https://git.openjdk.org/jdk/pull/22977#pullrequestreview-2540703533
PR Review Comment: https://git.openjdk.org/jdk/pull/22977#discussion_r1909302224
PR Review Comment: https://git.openjdk.org/jdk/pull/22977#discussion_r1909303094
PR Review Comment: https://git.openjdk.org/jdk/pull/22977#discussion_r1909297406