JBR-7481 Add a test for mouse entered/exit events

Use the robot to find the points when the mouse
entered event is sent to the popup when the mouse
enters through a rounded corner, and the similar
point for entering the outer window when exiting
through such a corner.

Once the points are found, move the mouse back
and forth to that point, but not beyond.
The correct behavior is that when the mouse
enters the popup, a mouse exited event is sent
to the outer frame and vice versa.
Therefore, every mouse entered/exited event
should be received exactly once.

Use reflection to set the rounded corners,
as JBR API isn't available in tests.

test/jdk/jb/java/awt/event/MouseEvent/MouseEnterExitMacRoundedCornersTest.java

@@ -0,0 +1,204 @@
+/*
+ * Copyright 2024 JetBrains s.r.o.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.awt.Color;
+import java.awt.Component;
+import java.awt.Dimension;
+import java.awt.EventQueue;
+import java.awt.Frame;
+import java.awt.Point;
+import java.awt.Robot;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
+import java.awt.event.MouseListener;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Supplier;
+import javax.swing.JLabel;
+import javax.swing.JFrame;
+import javax.swing.PopupFactory;
+import javax.swing.WindowConstants;
+import java.awt.Cursor;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.awt.Window;
+import sun.lwawt.macosx.CPlatformWindow;
+
+/*
+ * @test
+ * @key headful
+ * @requires (os.family == "mac")
+ * @modules java.desktop/sun.lwawt.macosx:+open java.desktop/sun.awt
+ * @summary Test mouse entered/exit events on macOS with rounded corners
+ * @run main MouseEnterExitMacRoundedCornersTest
+ */
+public class MouseEnterExitMacRoundedCornersTest {
+
+    private static MouseCounter windowMouseListener;
+    private static MouseCounter popupMouseListener;
+    private static Window window;
+    private static Window popupWindow;
+    private volatile static Point popupAt;
+
+    private static void showWindow() {
+        window = new JFrame();
+        windowMouseListener = new MouseCounter();
+        window.addMouseListener(windowMouseListener);
+        window.setSize(400, 300);
+        window.addWindowListener(new WindowAdapter() {
+            @Override
+            public void windowOpened(WindowEvent e) {
+                showPopup(window);
+            }
+        });
+        window.setVisible(true);
+    }
+
+    private static void showPopup(Component owner) {
+        var factory = PopupFactory.getSharedInstance();
+        var helloWorld = new JLabel();
+        helloWorld.setPreferredSize(new Dimension(200, 100));
+        helloWorld.setOpaque(true);
+        var popup = factory.getPopup(owner, helloWorld, 100, 100);
+        var window = getWindowParent(helloWorld);
+        popupMouseListener = new MouseCounter();
+        window.addMouseListener(popupMouseListener);
+        setRoundedCorners(window, new Object[] {8.0f, 1, Color.BLACK});
+        popupWindow = window;
+        popup.show();
+    }
+
+    private static void setRoundedCorners(Window window, Object[] args) {
+        try {
+            var method = CPlatformWindow.class.getDeclaredMethod("setRoundedCorners", Window.class, Object.class);
+            method.setAccessible(true);
+            method.invoke(null, window, args);
+        } catch (java.lang.Exception e) {
+            throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
+        }
+    }
+
+    private static Window getWindowParent(JLabel helloWorld) {
+        Component window = helloWorld;
+        while (window != null) {
+            window = window.getParent();
+            if (window instanceof Window) {
+                break;
+            }
+        }
+        return (Window) window;
+    }
+
+    public static void main(String[] args) throws Exception {
+        try {
+            Robot robot = new Robot();
+            robot.setAutoDelay(100);
+            robot.setAutoWaitForIdle(true);
+
+            EventQueue.invokeAndWait(MouseEnterExitMacRoundedCornersTest::showWindow);
+            robot.waitForIdle();
+
+            EventQueue.invokeAndWait(() -> {
+                popupAt = popupWindow.getLocationOnScreen();
+            });
+
+            int popupEnterPoint = findPoint(robot, popupAt, -5, +10, () -> popupMouseListener.enteredCount.get() > 0);
+            moveBackAndForth(robot, popupAt, -5, popupEnterPoint);
+
+            int frameEnterPoint = findPoint(robot, popupAt, +10, -5, () -> windowMouseListener.enteredCount.get() > 0);
+            moveBackAndForth(robot, popupAt, +10, frameEnterPoint);
+
+            System.out.println("Test PASSED");
+        } finally {
+            EventQueue.invokeAndWait(() -> {
+                if (window != null) {
+                    window.dispose();
+                }
+                if (popupWindow != null) {
+                    popupWindow.dispose();
+                }
+            });
+        }
+    }
+
+    private static int findPoint(Robot robot, Point popupAt, int start, int end, Supplier<Boolean> condition) throws Exception {
+        robot.mouseMove(popupAt.x + start, popupAt.y + start);
+        robot.waitForIdle();
+        resetCounters();
+        return move(robot, popupAt, start, end, condition);
+    }
+
+    private static void moveBackAndForth(Robot robot, Point popupAt, int start, int end) throws Exception {
+        robot.mouseMove(popupAt.x + start, popupAt.y + start);
+        robot.waitForIdle();
+        resetCounters();
+        move(robot, popupAt, start, end, null);
+        move(robot, popupAt, end, start, null);
+        assertEnteredExited();
+    }
+
+    private static void resetCounters() {
+        windowMouseListener.enteredCount.set(0);
+        windowMouseListener.exitedCount.set(0);
+        popupMouseListener.enteredCount.set(0);
+        popupMouseListener.exitedCount.set(0);
+    }
+
+    private static int move(Robot robot, Point popupAt, int start, int end, Supplier<Boolean> condition) throws Exception {
+        for (int offset = start; start < end ? offset <= end : offset >= end; offset = (start < end ? offset + 1 : offset - 1)) {
+            if (condition != null && condition.get()) {
+                return offset;
+            }
+            robot.mouseMove(popupAt.x + offset, popupAt.y + offset);
+        }
+        return -1;
+    }
+
+    private static void assertEnteredExited() {
+        var enteredWindow = windowMouseListener.enteredCount.get();
+        var exitedWindow = windowMouseListener.exitedCount.get();
+        var enteredPopup = popupMouseListener.enteredCount.get();
+        var exitedPopup = popupMouseListener.exitedCount.get();
+        if (enteredWindow != 1 || exitedWindow != 1 || enteredPopup != 1 || exitedPopup != 1) {
+            throw new RuntimeException(
+                    "Moved the mouse back and forth, expected to enter/exit both the popup and window exactly once, but got: "
+                            + "enteredWindow=" + enteredWindow + ", exitedWindow=" + exitedWindow + ", "
+                            + "enteredPopup=" + enteredPopup + ", exitedPopup=" + exitedPopup
+            );
+        }
+    }
+
+    private static class MouseCounter extends MouseAdapter {
+        final AtomicInteger enteredCount = new AtomicInteger();
+        final AtomicInteger exitedCount = new AtomicInteger();
+
+        @Override
+        public void mouseEntered(MouseEvent e) {
+            enteredCount.incrementAndGet();
+        }
+
+        @Override
+        public void mouseExited(MouseEvent e) {
+            exitedCount.incrementAndGet();
+        }
+    };
+}