Fix test leak detection in JUnit tests

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

@@ -18,8 +18,8 @@
 import java.util.List;
 
 import org.eclipse.swt.graphics.Resource;
-import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.BeforeAll;
+import org.junit.platform.suite.api.AfterSuite;
+import org.junit.platform.suite.api.BeforeSuite;
 import org.junit.platform.suite.api.SelectClasses;
 import org.junit.platform.suite.api.Suite;
 
@@ -79,8 +79,8 @@
 public class AllNonBrowserTests {
 	private static List<Error> leakedResources;
 
-	@BeforeAll
-	public static void beforeClass() {
+	@BeforeSuite
+	public static void beforeSuite() {
 		// Set up ResourceTracked to detect any leaks
 		leakedResources = new ArrayList<> ();
 		Resource.setNonDisposeHandler (error -> {
@@ -93,11 +93,11 @@ public static void beforeClass() {
 
 	/*
 	 * It would be easier to understand if errors here were reported
-	 * through  a test and not through @AfterClass, but this is a
+	 * through  a test and not through @AfterSuite, but this is a
 	 * suite class and not a test class, so it can't have tests.
 	 */
-	@AfterAll
-	public static void afterClass() {
+	@AfterSuite
+	public static void afterSuite() {
 		// Run GC in order do detect any outstanding leaks
 		System.gc ();
 		// And wait a bit to let Resource.ResourceTracker, that is

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

@@ -96,7 +96,13 @@ public void test_Validate() throws Exception {
 		assertEquals(0, imageDataComparator().compare(imageData, getContents()));
 
 		assertThrows(IllegalArgumentException.class, () -> setContents(""));
-		assertThrows(IllegalArgumentException.class, () -> setContents(new Image(display, imageData)));
+		Image image = new Image(display, imageData);
+		try {
+			// verify that ImageTransfer rejects actual images, as ImageData is required
+			assertThrows(IllegalArgumentException.class, () -> setContents(image));
+		} finally {
+			image.dispose();
+		}
 		assertThrows(IllegalArgumentException.class, () -> setContents(new Object()));
 	}
 

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

@@ -1028,16 +1028,20 @@ public void test_bug1288_createGCFromImageFromNonDisplayThread() throws Interrup
 public void test_noMemoryLeakAfterDispose() {
 	GC testGC = new GC(display);
 	Image image = new Image(display, 1, 1);
-	testGC.setFont(display.getSystemFont());
-	testGC.setClipping(new Rectangle(0, 0, 2, 2));
-	testGC.drawImage(image, 0, 0);
-	testGC.drawText("Test", 0, 0);
-	testGC.drawLine(0, 0, 5, 5);
-	WeakReference<GC> testGCReference = new WeakReference<>(testGC);
-	testGC.dispose();
-	testGC = null;
-	System.gc();
-	assertNull(testGCReference.get());
+	try {
+		testGC.setFont(display.getSystemFont());
+		testGC.setClipping(new Rectangle(0, 0, 2, 2));
+		testGC.drawImage(image, 0, 0);
+		testGC.drawText("Test", 0, 0);
+		testGC.drawLine(0, 0, 5, 5);
+		WeakReference<GC> testGCReference = new WeakReference<>(testGC);
+		testGC.dispose();
+		testGC = null;
+		System.gc();
+		assertNull(testGCReference.get());
+	} finally {
+		image.dispose();
+	}
 }
 
 /* custom */

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

@@ -1072,11 +1072,15 @@ public void test_imageDataIsCached() {
 		return imagePath;
 	};
 	Image fileNameProviderImage = new Image(display, imageFileNameProvider);
-	callCount.set(0);
-	fileNameProviderImage.getImageData(100);
-	fileNameProviderImage.getImageData(100);
-	fileNameProviderImage.getImageData(100);
-	assertEquals(0, callCount.get());
+	try {
+		callCount.set(0);
+		fileNameProviderImage.getImageData(100);
+		fileNameProviderImage.getImageData(100);
+		fileNameProviderImage.getImageData(100);
+		assertEquals(0, callCount.get());
+	} finally {
+		fileNameProviderImage.dispose();
+	}
 }
 
 @Test