tester: Use CompositeClassLoader for TCCL when loading tests

aQute.libg/src/aQute/libg/classloaders/CompositeClassLoader.java

@@ -0,0 +1,121 @@
+package aQute.libg.classloaders;
+
+import java.io.IOException;
+import java.net.URL;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Objects;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+public class CompositeClassLoader extends ClassLoader {
+	@SafeVarargs
+	public static ClassLoader of(ClassLoader... elements) {
+		List<ClassLoader> list = Arrays.stream(elements)
+			.filter(Objects::nonNull)
+			.distinct()
+			.collect(Collectors.toList());
+		int size = list.size();
+		if (size == 0) {
+			throw new IllegalArgumentException("Must have at least one element");
+		}
+		if (size == 1) {
+			return list.get(0);
+		}
+		return new CompositeClassLoader(list);
+	}
+
+	private final List<ClassLoader> elements;
+
+	private CompositeClassLoader(List<ClassLoader> elements) {
+		super(null); // no parent
+		this.elements = List.copyOf(elements); // immutable list
+	}
+
+	@Override
+	public Class<?> loadClass(String name) throws ClassNotFoundException {
+		Stream<Class<?>> classes = elements.stream()
+			.<Class<?>>map(loader -> {
+				try {
+					return loader.loadClass(name);
+				} catch (ClassNotFoundException e) {
+					return null;
+				}
+			})
+			.filter(Objects::nonNull);
+		Class<?> result = classes.findFirst()
+			.orElseThrow(() -> new ClassNotFoundException(name));
+		return result;
+	}
+
+	@Override
+	public URL getResource(String name) {
+		Stream<URL> resources = elements.stream()
+			.<URL>map(loader -> loader.getResource(name))
+			.filter(Objects::nonNull);
+		URL result = resources.findFirst()
+			.orElse(null);
+		return result;
+	}
+
+	@Override
+	public Enumeration<URL> getResources(String name) throws IOException {
+		Stream<URL> resources = elements.stream()
+			.<Enumeration<URL>>map(loader -> {
+				try {
+					return loader.getResources(name);
+				} catch (IOException e) {
+					return Collections.emptyEnumeration();
+				}
+			})
+			.map(enumeration -> Spliterators.spliteratorUnknownSize(enumeration.asIterator(), Spliterator.ORDERED))
+			.flatMap(spliterator -> StreamSupport.stream(spliterator, false))
+			.distinct();
+		Enumeration<URL> result = new SpliteratorEnumeration<>(resources.spliterator());
+		return result;
+	}
+
+	final static class SpliteratorEnumeration<T> implements Enumeration<T>, Consumer<T> {
+		private final Spliterator<T> spliterator;
+		private boolean hasNext = false;
+		private T next;
+
+		SpliteratorEnumeration(Spliterator<T> spliterator) {
+			this.spliterator = Objects.requireNonNull(spliterator);
+		}
+
+		@Override
+		public boolean hasMoreElements() {
+			if (hasNext) {
+				return true;
+			}
+			if (spliterator.tryAdvance(this)) {
+				return hasNext = true;
+			}
+			return false;
+		}
+
+		@Override
+		public T nextElement() {
+			if (hasMoreElements()) {
+				T t = next;
+				hasNext = false;
+				next = null;
+				return t;
+			}
+			throw new NoSuchElementException();
+		}
+
+		@Override
+		public void accept(T t) {
+			next = t;
+		}
+	}
+}

aQute.libg/src/aQute/libg/classloaders/package-info.java

@@ -0,0 +1,4 @@
+@Version("1.1.0")
+package aQute.libg.classloaders;
+
+import org.osgi.annotation.versioning.Version;

biz.aQute.tester.junit-platform/src/aQute/tester/junit/platform/Activator.java

@@ -60,6 +60,7 @@
 import org.osgi.util.tracker.ServiceTracker;
 
 import aQute.junit.system.BndSystem;
+import aQute.libg.classloaders.CompositeClassLoader;
 import aQute.tester.bundle.engine.BundleEngine;
 import aQute.tester.bundle.engine.discovery.BundleSelector;
 import aQute.tester.junit.platform.reporting.legacy.xml.LegacyXmlReportGeneratingListener;
@@ -129,7 +130,7 @@ public void run() {
 		// We can be started on our own thread or from the main code
 		thread = Thread.currentThread();
 		final ClassLoader contextClassLoader = thread.getContextClassLoader();
-		thread.setContextClassLoader(getClass().getClassLoader());
+		thread.setContextClassLoader(CompositeClassLoader.of(getClass().getClassLoader(), contextClassLoader));
 		try {
 			launcher = LauncherFactory.create(LauncherConfig.builder()
 				.enableTestEngineAutoRegistration(false)