Migrate try-catch-fail patterns to assertThrows in tests

Replace legacy try { ...; fail(...); } catch (XException e) {}
patterns with JUnit 5 assertThrows().

Also fix a latent test bug: offsets[offsets.length] always threw
ArrayIndexOutOfBoundsException before getLineInformationOfOffset
was called; replaced with a properly computed out-of-bounds offset.

Author: HeikoKlare

tests/org.eclipse.e4.ui.tests.css.core/META-INF/MANIFEST.MF

@@ -15,6 +15,7 @@ Export-Package: org.eclipse.e4.ui.tests.css.core;x-internal:=true,
  org.eclipse.e4.ui.tests.css.core.util;x-internal:=true
 Automatic-Module-Name: org.eclipse.e4.ui.tests.css.core
 Import-Package: org.junit.jupiter.api;version="[5.14.0,6.0.0)",
+ org.junit.jupiter.api.function;version="[5.14.0,6.0.0)",
  org.junit.platform.suite.api;version="[1.14.0,2.0.0)",
  org.w3c.css.sac;version="1.3.0"
 Bundle-Vendor: %Bundle-Vendor

tests/org.eclipse.e4.ui.tests.css.core/src/org/eclipse/e4/ui/tests/css/core/parser/SelectorTest.java

@@ -16,9 +16,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.fail;
-
-import java.io.IOException;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.eclipse.e4.ui.css.core.engine.CSSEngine;
 import org.eclipse.e4.ui.tests.css.core.util.ParserTestUtil;
@@ -69,12 +67,7 @@ void testAttributeSelector() throws Exception {
 	}
 
 	@Test
-	void testErrorAttributeSelector() throws IOException {
-		try {
-			engine.parseSelectors("*[class='Class1'"); // missing ']'
-			fail("Parser should have errored on missing bracket");
-		} catch (CSSParseException e) {
-			// ignore
-		}
+	void testErrorAttributeSelector() {
+		assertThrows(CSSParseException.class, () -> engine.parseSelectors("*[class='Class1'")); // missing ']'
 	}
 }

tests/org.eclipse.e4.ui.tests/META-INF/MANIFEST.MF

@@ -39,6 +39,7 @@ Import-Package: jakarta.annotation,
  jakarta.inject,
  org.osgi.service.event,
  org.junit.jupiter.api;version="[5.14.0,6.0.0)",
+ org.junit.jupiter.api.function;version="[5.14.0,6.0.0)",
  org.junit.jupiter.api.extension;version="[5.14.0,6.0.0)",
  org.junit.platform.suite.api;version="[1.14.0,2.0.0)",
  org.opentest4j

tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EModelServiceFindTest.java

@@ -14,11 +14,11 @@
  ******************************************************************************/
 package org.eclipse.e4.ui.tests.application;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -259,26 +259,9 @@ public void testFindElements_NullCheck() {
 		EModelService modelService = application.getContext().get(EModelService.class);
 		assertNotNull(modelService);
 
-		try {
-			modelService.find("a", null);
-			fail("An exception should have prevented a null parameter to find(*)");
-		} catch (IllegalArgumentException e) {
-			// expected
-		}
-
-		try {
-			modelService.findElements(null, null, null);
-			fail("An exception should have prevented a null parameter to findElements(*)");
-		} catch (IllegalArgumentException e) {
-			// expected
-		}
-
-		try {
-			modelService.findElements(null, null, null, null, EModelService.ANYWHERE);
-			fail("An exception should have prevented a null parameter to findElements(*)");
-		} catch (IllegalArgumentException e) {
-			// expected
-		}
+		assertThrows(IllegalArgumentException.class, () -> modelService.find("a", null));
+		assertThrows(IllegalArgumentException.class, () -> modelService.findElements(null, null, null));
+		assertThrows(IllegalArgumentException.class, () -> modelService.findElements(null, null, null, null, EModelService.ANYWHERE));
 	}
 
 	@Test

tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/ModelRobustnessTest.java

@@ -16,7 +16,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.List;
 import org.eclipse.e4.ui.internal.workbench.E4XMIResource;
@@ -41,12 +41,8 @@ public void testLoadingInvalidContainments() {
 		ResourceSet set = new ResourceSetImpl();
 		Resource resource = null;
 
-		try {
-			resource = set.getResource(uri, true);
-			fail("This should have thrown an exception");
-		} catch (Exception e) {
-			resource = set.getResource(uri, false);
-		}
+		assertThrows(Exception.class, () -> set.getResource(uri, true));
+		resource = set.getResource(uri, false);
 
 		assertNotNull(resource);
 		assertEquals(E4XMIResource.class, resource.getClass());
@@ -75,17 +71,10 @@ public void testAddingInvalidElements() {
 		MApplication app = MApplicationFactory.INSTANCE.createApplication();
 		List l = app.getChildren();
 		l.add(MBasicFactory.INSTANCE.createWindow());
-		try {
-			l.add(MBasicFactory.INSTANCE.createPart());
-			fail("The adding of this should have failed");
-		} catch (IllegalArgumentException | ArrayStoreException | ClassCastException e) {
-			// EList.add says this is the expected exception, although testing
-			// indicates its one of the two previous exceptions that is really
-			// thrown.
-			// See bug 407539
-		} catch (Exception e) {
-			throw new RuntimeException(e);
-		}
+		// EList.add says IllegalArgumentException is the expected exception, although
+		// testing indicates ArrayStoreException or ClassCastException may be thrown.
+		// See bug 407539
+		assertThrows(RuntimeException.class, () -> l.add(MBasicFactory.INSTANCE.createPart()));
 
 		l.add(MBasicFactory.INSTANCE.createWindow());
 		assertEquals(2, l.size());

tests/org.eclipse.jface.tests/src/org/eclipse/jface/tests/dialogs/DialogSettingsTest.java

@@ -19,8 +19,8 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.IOException;
 import java.io.StringReader;
@@ -455,14 +455,9 @@ private static void testPutAndGetWithTitle(DialogSettingsChecker dialogSettingsC
 	}
 
 	@Test
-	@SuppressWarnings("resource")
 	public void testSaveWithIOException() {
 		final DialogSettings settings = new DialogSettings("test");
-		try {
-			settings.save(new BrokenWriter());
-			fail("IOException expected");
-		} catch (IOException e) {
-		}
+		assertThrows(IOException.class, () -> settings.save(new BrokenWriter()));
 	}
 
 	private static class BrokenWriter extends Writer {

tests/org.eclipse.jface.tests/src/org/eclipse/jface/tests/labelProviders/DecoratingStyledCellLabelProviderTest.java

@@ -19,8 +19,8 @@
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNotSame;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
 
 import org.eclipse.core.runtime.AssertionFailedException;
 import org.eclipse.jface.resource.JFaceResources;
@@ -238,12 +238,7 @@ public void testGetDecorationContext() {
 
 	@Test
 	public void testSetDecorationContext() {
-		try {
-			getDecoratingStyledLabelProvider().setDecorationContext(null);
-			fail("DecoratingStyledCellLabelProvider.setDecorationContext did not throw an exception when passed null");
-		} catch (AssertionFailedException e) {
-			// A Good Thing.
-		}
+		assertThrows(AssertionFailedException.class, () -> getDecoratingStyledLabelProvider().setDecorationContext(null));
 	}
 
 	@Test

tests/org.eclipse.jface.tests/src/org/eclipse/jface/tests/labelProviders/IDecorationContextTest.java

@@ -15,7 +15,7 @@
 package org.eclipse.jface.tests.labelProviders;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.eclipse.core.runtime.AssertionFailedException;
 import org.eclipse.jface.viewers.DecoratingStyledCellLabelProvider;
@@ -141,12 +141,7 @@ public void testDefaultContextIsUsed() {
 	@Test
 	public void testSetDecorationContextNull() {
 		DecoratingStyledCellLabelProvider label = getDecoratingStyledCellLabelProvider(false);
-		try {
-			label.setDecorationContext(null);
-			fail("DecoratingStyledCellLabelProvider.setDecorationContext did not throw an exception when passed null");
-		} catch (AssertionFailedException e) {
-			// A Good Thing.
-		}
+		assertThrows(AssertionFailedException.class, () -> label.setDecorationContext(null));
 	}
 
 }

tests/org.eclipse.jface.text.tests/src/org/eclipse/jface/text/tests/TextPresentationTest.java

@@ -15,8 +15,8 @@
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -1256,23 +1256,17 @@ public void testApplyTextPresentation() {
 	public void testIterator() {
 		// Test read over iterator end
 		Iterator<StyleRange> e= fTextPresentation.getAllStyleRangeIterator();
-		try {
+		assertThrows(NoSuchElementException.class, () -> {
 			for (int i= 0; i < 1000; i++) {
 				e.next();
 			}
-			fail("Iterator has no end.");
-		} catch (NoSuchElementException ex) {
-			// expected
-		}
-		e= fTextPresentation.getNonDefaultStyleRangeIterator();
-		try {
+		});
+		Iterator<StyleRange> e2= fTextPresentation.getNonDefaultStyleRangeIterator();
+		assertThrows(NoSuchElementException.class, () -> {
 			for (int i= 0; i < 1000; i++) {
-				e.next();
+				e2.next();
 			}
-			fail("Iterator has no end.");
-		} catch (NoSuchElementException ex) {
-			// expected
-		}
+		});
 	}
 
 	// helper method required as long as TextPresentation methods manipulate given arguments