Migrate TestFailReporter to JUnit 5 TestFailExtension

Extracts the TestFailReporter inner class from FileBufferFunctions
into a standalone TestFailExtension class that implements
JUnit 5's TestWatcher interface.

Updates FileBufferFunctions to use @RegisterExtension with the
new extension.

Author: vogella

tests/org.eclipse.core.filebuffers.tests/src/org/eclipse/core/filebuffers/tests/FileBufferFunctions.java

@@ -28,19 +28,13 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
-import org.junit.jupiter.api.extension.ExtensionContext;
-import org.junit.jupiter.api.extension.TestWatcher;
 
 
 import org.eclipse.core.filesystem.EFS;
 import org.eclipse.core.filesystem.IFileInfo;
 import org.eclipse.core.filesystem.IFileStore;
 
-import org.eclipse.core.runtime.ILog;
 import org.eclipse.core.runtime.IPath;
-import org.eclipse.core.runtime.IStatus;
-import org.eclipse.core.runtime.Platform;
-import org.eclipse.core.runtime.Status;
 
 import org.eclipse.core.resources.IProject;
 
@@ -104,26 +98,7 @@ protected IPath getPath() {
 	}
 
 	@RegisterExtension
-	public TestFailReporter failReporter= new TestFailReporter();
-
-	public static class TestFailReporter implements TestWatcher {
-
-		private static final String BUNDLE_ID= "org.eclipse.core.filebuffers.tests";
-
-		ILog log= ILog.of(Platform.getBundle(BUNDLE_ID));
-
-		@Override
-		public void testFailed(ExtensionContext context, Throwable e) {
-			IStatus status= new Status(IStatus.ERROR, BUNDLE_ID, "FAIL in " + context.getDisplayName(), e);
-			log.log(status);
-		}
-
-		@Override
-		public void testSuccessful(ExtensionContext context) {
-			IStatus status= new Status(IStatus.INFO, BUNDLE_ID, "PASS in " + context.getDisplayName());
-			log.log(status);
-		}
-	}
+	public TestFailExtension failReporter= new TestFailExtension();
 
 	/*
 	 * Tests getLocation.

tests/org.eclipse.core.filebuffers.tests/src/org/eclipse/core/filebuffers/tests/TestFailExtension.java

@@ -0,0 +1,41 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2015 IBM Corporation and others.
+ *
+ * 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
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.filebuffers.tests;
+
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.TestWatcher;
+
+import org.eclipse.core.runtime.ILog;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.Status;
+
+public class TestFailExtension implements TestWatcher {
+
+	private static final String BUNDLE_ID= "org.eclipse.core.filebuffers.tests";
+
+	ILog log= ILog.of(Platform.getBundle(BUNDLE_ID));
+
+	@Override
+	public void testFailed(ExtensionContext context, Throwable e) {
+		IStatus status= new Status(IStatus.ERROR, BUNDLE_ID, "FAIL in " + context.getDisplayName(), e);
+		log.log(status);
+	}
+
+	@Override
+	public void testSuccessful(ExtensionContext context) {
+		IStatus status= new Status(IStatus.INFO, BUNDLE_ID, "PASS in " + context.getDisplayName());
+		log.log(status);
+	}
+}