Avoid reading org.eclipse.swt.* properties too early

The value of org.eclipse.swt.internal.gdk.backend is not set until a display
is created at least once since this value is assigned in the Display constructor.
Normally tests are run in such an order that SwtTestUtil isn't accessed until
after the first Display is created. Make sure to create a display before calling
SwtTestUtil.isX11().

A similar problem exists for org.eclipse.swt.internal.gtk.version
in relation to OS.

This is a fix for a regression caused by moving the setting of
org.eclipse.swt.internal.gdk.backend from OS to Display in
5d67ce6. That commit fixed
an unrelated bug, but sometimes bad initialization of isX11 is an
unintended side effect causing tests to be skipped or run in
unexpected ways since isX11 was not correct.

Author: jonahgraham

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

@@ -100,10 +100,30 @@ public class SwtTestUtil {
 	/** Useful if you want some tests not to run on Jenkins with user "genie.platform" */
 	public final static boolean isRunningOnContinousIntegration = isGTK && ("genie.platform".equalsIgnoreCase(System.getProperty("user.name")));
 
-	public final static boolean isX11 = isGTK
-			&& "x11".equals(System.getProperty("org.eclipse.swt.internal.gdk.backend"));
-	public final static boolean isGTK4 = isGTK
-			&& System.getProperty("org.eclipse.swt.internal.gtk.version", "").startsWith("4");
+	/**
+	 * The value of org.eclipse.swt.internal.gdk.backend is not set until a display
+	 * is created at least once since this value is assigned in the Display
+	 * constructor. Normally tests are run in such an order that SwtTestUtil isn't
+	 * accessed until after the first Display is created.
+	 *
+	 * Rather than requiring all users of SwtTestUtil to be careful with their
+	 * access to SwtTestUtil, this "is..." is a method instead of a constant.
+	 */
+	public final static boolean isX11() {
+		return isGTK && "x11".equals(System.getProperty("org.eclipse.swt.internal.gdk.backend"));
+	}
+
+	/**
+	 * The value of org.eclipse.swt.internal.gtk.version is not set until after OS
+	 * is accessed for the first time. Normally tests are run in such an order that
+	 * SwtTestUtil isn't accessed until after the first time OS is used.
+	 *
+	 * Rather than requiring all users of SwtTestUtil to be careful with their
+	 * access to SwtTestUtil, this "is..." is a method instead of a constant.
+	 */
+	public final static boolean isGTK4() {
+		return isGTK && System.getProperty("org.eclipse.swt.internal.gtk.version", "").startsWith("4");
+	}
 
 	/**
 	 * The palette used by images. See {@link #getAllPixels(Image)} and {@link #createImage}

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

@@ -80,7 +80,7 @@ public void setUp() {
 	}
 
 	private void sleep() throws InterruptedException {
-		if (SwtTestUtil.isGTK4) {
+		if (SwtTestUtil.isGTK4()) {
 			/**
 			 * TODO remove all uses of sleep and change them to processEvents with the
 			 * suitable conditional, or entirely remove them
@@ -351,7 +351,7 @@ public void test_setContents() throws Exception {
 			String result = runOperationInThread(remote::getStringContents);
 			assertEquals(helloWorld, result);
 		} catch (Exception | AssertionError e) {
-			if (SwtTestUtil.isGTK4 && !SwtTestUtil.isX11) {
+			if (SwtTestUtil.isGTK4() && !SwtTestUtil.isX11()) {
 				// TODO make the code + test stable
 				throw new RuntimeException(
 						"This test is really unstable on wayland backend, at least with Ubuntu 25.04", e);

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

@@ -1247,7 +1247,7 @@ public void test_setCursorLocationII(TestInfo info) {
 		display.setCursorLocation(location.x, location.y); // don't put cursor into a corner, since that could trigger special platform events
 		drainEventQueue(display, 150); // workaround for https://bugs.eclipse.org/492569
 		Point actual = display.getCursorLocation();
-		if (!BUG_492569 && SwtTestUtil.isX11) {
+		if (!BUG_492569 && SwtTestUtil.isX11()) {
 			if (!location.equals(actual)) {
 				Screenshots.takeScreenshot(getClass(), info.getDisplayName()); // Bug 528968 This call causes crash on Wayland.
 				fail("\nExpected:"+location.toString()+"  Actual:"+actual.toString());
@@ -1279,7 +1279,7 @@ public void test_setCursorLocationLorg_eclipse_swt_graphics_Point(TestInfo info)
 		}
 		drainEventQueue(display, 150); // workaround for https://bugs.eclipse.org/492569
 		Point actual = display.getCursorLocation();
-		if (!BUG_492569 && SwtTestUtil.isX11) {
+		if (!BUG_492569 && SwtTestUtil.isX11()) {
 			if (!location.equals(actual)) {
 				Screenshots.takeScreenshot(getClass(), info.getDisplayName()); // Bug 528968 This call causes crash on Wayland.
 				fail("\nExpected:"+location.toString()+"  Actual:"+actual.toString());

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

@@ -460,7 +460,7 @@ public void test_getImeInputMode() {
 @Test
 public void test_getLocation() {
 	//Setting location for Windows is not supported in GTK4
-	if (SwtTestUtil.isGTK4) {
+	if (SwtTestUtil.isGTK4()) {
 		return;
 	}
 	shell.setLocation(10,15);
@@ -656,7 +656,7 @@ public void test_setBoundsLorg_eclipse_swt_graphics_Rectangle() {
  */
 @Test
 public void test_activateEventSend() throws InterruptedException {
-	assumeTrue((SwtTestUtil.isGTK && SwtTestUtil.isX11) || SwtTestUtil.isGTK4,
+	assumeTrue((SwtTestUtil.isGTK && SwtTestUtil.isX11()) || SwtTestUtil.isGTK4(),
 			"Feature only works on GTK3 in x11 or GTK4 - https://bugs.eclipse.org/436841");
 
 	AtomicBoolean activateCalled = new AtomicBoolean();
@@ -708,7 +708,7 @@ public void test_activateEventSend() throws InterruptedException {
  */
 @Test
 public void test_setBounds() throws Exception {
-	if (SwtTestUtil.isX11) {
+	if (SwtTestUtil.isX11()) {
 		Rectangle bounds = new Rectangle(100, 200, 200, 200);
 		Rectangle bounds2 = new Rectangle(150, 250, 250, 250);
 
@@ -1037,7 +1037,7 @@ public void test_Issue450_NoShellActivateOnSetFocus() {
 @Override
 public void test_setLocationLorg_eclipse_swt_graphics_Point() {
 	//Setting location for Windows is not supported in GTK4
-	if (SwtTestUtil.isGTK4) {
+	if (SwtTestUtil.isGTK4()) {
 		return;
 	}
 	super.test_setLocationLorg_eclipse_swt_graphics_Point();
@@ -1047,7 +1047,7 @@ public void test_setLocationLorg_eclipse_swt_graphics_Point() {
 @Override
 public void test_setLocationII() {
 	//Setting location for Windows is not supported in GTK4
-	if (SwtTestUtil.isGTK4) {
+	if (SwtTestUtil.isGTK4()) {
 		return;
 	}
 	super.test_setLocationII();