Refactor tests a little in prep for dnd tests

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/graphics/ImageDataTestHelper.java

@@ -18,6 +18,7 @@
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Comparator;
 import java.util.Random;
 
 import org.eclipse.swt.graphics.Image;
@@ -212,6 +213,28 @@ public static BlitTestInfo blit(BlitTestInfo srcInfo, int dstInfo_depth, int dst
 		return new BlitTestInfo(dstInfo_depth, dstInfo_scale, dstInfo_byteOrder, dstInfo_isDirect, dst);
 	}
 
+	/**
+	 * Compares ImageData, allows for change in things like bit depth by comparing pixel values rather
+	 * that the raw data like {@link #assertImageDataEqual(ImageData, ImageData, ImageData)}
+	 */
+	public static Comparator<ImageData> imageDataComparator() {
+		return Comparator.<ImageData>comparingInt(d -> d.width) //
+				.thenComparing(d -> d.height) //
+				.thenComparing((ImageData firstData, ImageData secondData) -> {
+					for (int x = 0; x < firstData.width; x++) {
+						for (int y = 0; y < firstData.height; y++) {
+							if (firstData.getPixel(x, y) != secondData.getPixel(x, y)) {
+								return -1;
+							}
+							if (firstData.getAlpha(x, y) != secondData.getAlpha(x, y)) {
+								return -1;
+							}
+						}
+					}
+					return 0;
+				});
+	}
+
 	public static void assertImageDataEqual(ImageData source, ImageData actual, ImageData expected) {
 		if (TEST_BLIT_SHOW_IMAGES) {
 			Image[] images = new Image[3];

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/ClipboardBase.java

@@ -0,0 +1,188 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Kichwa Coders Canada, Inc.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.swt.tests.junit;
+
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assumptions.assumeFalse;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.dnd.Clipboard;
+import org.eclipse.swt.dnd.DND;
+import org.eclipse.swt.layout.RowLayout;
+import org.eclipse.swt.widgets.Button;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Label;
+import org.eclipse.swt.widgets.Shell;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.RepeatedTest;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * Base class for tests that test clipboard and transfer types
+ */
+public class ClipboardBase {
+
+	/**
+	 * See {@link #openAndFocusShell(boolean)} - some tests require user to actually
+	 * interact with the shell.
+	 *
+	 * Default to skipping tests requiring "real" activation on GHA and Jenkins.
+	 *
+	 * <code>true</code>: skip tests <code>false</code>: don't skip tests
+	 * <code>null</code>: unknown whether to skip tests yet
+	 */
+	private static Boolean skipTestsRequiringButtonPress = (Boolean.parseBoolean(System.getenv("GITHUB_ACTIONS"))
+			|| System.getenv("JOB_NAME") != null) ? true : null;
+	private static int uniqueId = 1;
+	protected Display display;
+	protected Shell shell;
+	protected Clipboard clipboard;
+	protected RemoteClipboard remote;
+
+	/**
+	 * Return the set of clipboards that are supported on this platform, this method
+	 * is referenced in the {@link MethodSource} annotations on the
+	 * {@link ParameterizedTest}s within this class.
+	 */
+	public static List<Integer> supportedClipboardIds() {
+		if (SwtTestUtil.isGTK) {
+			return List.of(DND.CLIPBOARD, DND.SELECTION_CLIPBOARD);
+		}
+		return List.of(DND.CLIPBOARD);
+	}
+
+	@BeforeEach
+	public void setUp() {
+		display = Display.getCurrent();
+		if (display == null) {
+			display = Display.getDefault();
+		}
+		clipboard = new Clipboard(display);
+	}
+
+	/**
+	 * Note: Wayland backend does not allow access to system clipboard from
+	 * non-focussed windows. So we have to create/open and focus a window here so
+	 * that clipboard operations work.
+	 *
+	 * Additionally, if we want to provide data to the clipboard, we require user
+	 * interaction on the created shell. Therefore if forSetContents is true the
+	 * tester needs to press a button for test to work.
+	 *
+	 * If there is no user interaction (button not pressed) then the test is
+	 * skipped, rather than failed, and subsequent tests requiring user interaction
+	 * as skipped too. See {@link #skipTestsRequiringButtonPress}
+	 */
+	protected void openAndFocusShell(boolean forSetContents) throws InterruptedException {
+		assertNull(shell);
+		shell = new Shell(display);
+
+		boolean requireUserPress = forSetContents && SwtTestUtil.isWayland();
+		if (requireUserPress) {
+			assumeFalse(skipTestsRequiringButtonPress != null && skipTestsRequiringButtonPress,
+					"Skipping tests that require user input");
+
+			AtomicBoolean pressed = new AtomicBoolean(false);
+			shell.setLayout(new RowLayout(SWT.VERTICAL));
+			Button button = new Button(shell, SWT.PUSH);
+			button.setText("Press me!");
+			button.addListener(SWT.Selection, (e) -> pressed.set(true));
+			button.setSize(200, 50);
+			Label label = new Label(shell, SWT.NONE);
+			label.setText("""
+					Press the button to tell Wayland that you really want this window to have access to clipboard.
+					This is needed on Wayland because only really focussed programs are allowed to write to the
+					global keyboard.
+
+					If you don't press this button soon, the test will be skipped and you won't be asked again.
+					""");
+			Label timeleft = new Label(shell, SWT.NONE);
+			timeleft.setText("Time left to press button: XXXXXXXXXXXXXXXXXXXX seconds");
+
+			SwtTestUtil.openShell(shell);
+
+			// If we know there is a tester pressing the buttons, allow them
+			// a little grace on the timeout. If we don't know if there is a
+			// tester around, skip tests fairly quickly and don't
+			// ask again.
+			int timeout = skipTestsRequiringButtonPress == null ? 1500 : 10000;
+			long startTime = System.nanoTime();
+			SwtTestUtil.processEvents(timeout, () -> {
+				long nowTime = System.nanoTime();
+				long timeLeft = nowTime - startTime;
+				long timeLeftMs = timeout - (timeLeft / 1_000_000);
+				double timeLeftS = timeLeftMs / 1_000.0d;
+				timeleft.setText("Time left to press button: " + timeLeftS + " seconds");
+				return pressed.get();
+			});
+			boolean userPressedButton = pressed.get();
+			if (userPressedButton) {
+				skipTestsRequiringButtonPress = false;
+			} else {
+				skipTestsRequiringButtonPress = true;
+				assumeTrue(false, "Skipping tests that require user input");
+			}
+		} else {
+			SwtTestUtil.openShell(shell);
+		}
+
+	}
+
+	/**
+	 * Note: Wayland backend does not allow access to system clipboard from
+	 * non-focussed windows. So we have to open and focus remote here so that
+	 * clipboard operations work.
+	 */
+	protected void openAndFocusRemote() throws Exception {
+		assertNull(remote);
+		remote = new RemoteClipboard();
+		remote.start();
+
+		/*
+		 * If/when OpenJDK Project Wakefield gets merged then we may need to wait for
+		 * button pressed on the swing app just like the SWT app. This may also be
+		 * needed if Wayland implementations get more restrictive on X apps too.
+		 */
+		// remote.waitForButtonPress();
+	}
+
+	@AfterEach
+	public void tearDown() throws Exception {
+		try {
+			if (remote != null) {
+				remote.stop();
+			}
+		} finally {
+			if (clipboard != null) {
+				clipboard.dispose();
+			}
+			if (shell != null) {
+				shell.dispose();
+			}
+			SwtTestUtil.processEvents();
+		}
+	}
+
+	/**
+	 * Make sure to always copy/paste unique strings - this ensures that tests run
+	 * under {@link RepeatedTest}s don't false pass because of clipboard value on
+	 * previous iteration.
+	 */
+	protected static String getUniqueTestString() {
+		return "Hello World " + uniqueId++;
+	}
+}