Defaults to SELF to preserve existing behavior.

Using CHILDREN has the same effect as declaring @ResourceLock on every @test method of a test class.

Issue: junit-team#3102

documentation/src/docs/asciidoc/release-notes/release-notes-5.10.0-M1.adoc

@@ -36,6 +36,9 @@ repository on GitHub.
   of the former. Please refer to the
   <<../user-guide/index.adoc#launcher-api-launcher-interceptors-custom, User Guide>> for
   details.
+* Introduced `@ResourceLock(target = SELF | CHILDREN)` where target defaults to SELF to
+  preserve existing behavior. Using CHILDREN has the same effect as declaring @ResourceLock
+  on every @Test method of a test class. Please refer to the <<../user-guide/writing-tests.adoc#specifying-target-for-resource-lock, User Guide. Writing Tests>> for details.
 
 [[release-notes-5.10.0-M1-junit-jupiter]]
 === JUnit Jupiter

documentation/src/docs/asciidoc/user-guide/writing-tests.adoc

@@ -2490,6 +2490,16 @@ to the same shared resource is running.
 include::{testDir}/example/SharedResourcesDemo.java[tags=user_guide]
 ----
 
+[[specifying-target-for-resource-lock]]
+You can declare a resource lock on the class level which will apply only to its children,
+and will not be applied to the class itself. This is useful if you want to keep `CONCURRENT`
+execution mode for each method.
+
+[source,java]
+----
+include::{testDir}/example/SharedResourcesChildrenTargetDemo.java[tags=user_guide]
+----
+
 
 [[writing-tests-built-in-extensions]]
 === Built-in Extensions

documentation/src/test/java/example/SharedResourcesChildrenTargetDemo.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2015-2023 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package example;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.parallel.ExecutionMode.CONCURRENT;
+import static org.junit.jupiter.api.parallel.ResourceAccessMode.READ;
+import static org.junit.jupiter.api.parallel.ResourceAccessMode.READ_WRITE;
+import static org.junit.jupiter.api.parallel.Resources.SYSTEM_OUT;
+import static org.junit.jupiter.api.parallel.Resources.SYSTEM_PROPERTIES;
+import static org.junit.jupiter.api.parallel.Resources.TIME_ZONE;
+
+import java.util.Properties;
+import java.util.TimeZone;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.parallel.Execution;
+import org.junit.jupiter.api.parallel.ResourceLock;
+import org.junit.jupiter.api.parallel.ResourceLockTarget;
+
+// tag::user_guide[]
+@Execution(CONCURRENT)
+@ResourceLock(value = TIME_ZONE, mode = READ, target = ResourceLockTarget.CHILDREN)
+class SharedResourcesChildrenTargetDemo {
+
+	private Properties backup;
+
+	@BeforeEach
+	void backup() {
+		backup = new Properties();
+		backup.putAll(System.getProperties());
+	}
+
+	@AfterEach
+	void restore() {
+		System.setProperties(backup);
+	}
+
+	@Test
+	@ResourceLock(value = SYSTEM_PROPERTIES, mode = READ)
+	void usePropertiesAndTimeZoneWithoutModification() {
+		assertNull(System.getProperty("my.prop"));
+	}
+
+	@Test
+	@ResourceLock(value = SYSTEM_PROPERTIES, mode = READ)
+	void usePropertiesAndTimeZoneWithoutModificationAgain() {
+		assertNull(System.getProperty("my.prop"));
+	}
+
+	@Test
+	@ResourceLock(value = SYSTEM_PROPERTIES, mode = READ_WRITE)
+	void canSetCustomPropertyToTimeZone() {
+		String timezone = TimeZone.getDefault().getDisplayName();
+		System.setProperty("my.timezone", timezone);
+		assertEquals(timezone, System.getProperty("my.timezone"));
+	}
+
+}
+// end::user_guide[]

junit-jupiter-api/src/main/java/org/junit/jupiter/api/parallel/ResourceLock.java

@@ -40,6 +40,9 @@
  * <p>Since JUnit Jupiter 5.4, this annotation is {@linkplain Inherited inherited}
  * within class hierarchies.
  *
+ * <p>Since JUnit Jupiter 5.10, this annotation can be used to specify the target
+ * of the lock with {@link ResourceLockTarget}.
+ *
  * @see Isolated
  * @see Resources
  * @see ResourceAccessMode
@@ -69,4 +72,13 @@
 	 */
 	ResourceAccessMode mode() default ResourceAccessMode.READ_WRITE;
 
+	/**
+	 * Resource lock target.
+	 *
+	 * <p>Defaults to {@link ResourceLockTarget#SELF SELF}.
+	 *
+	 * @see ResourceLockTarget
+	 */
+	ResourceLockTarget target() default ResourceLockTarget.SELF;
+
 }

junit-jupiter-api/src/main/java/org/junit/jupiter/api/parallel/ResourceLockTarget.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2015-2023 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package org.junit.jupiter.api.parallel;
+
+import static org.apiguardian.api.API.Status.EXPERIMENTAL;
+
+import org.apiguardian.api.API;
+
+/**
+ *	Indicates the target of a {@link ResourceLock}.
+ *
+ * @since 5.10
+ * @see ResourceLock
+ */
+@API(status = EXPERIMENTAL, since = "5.10")
+public enum ResourceLockTarget {
+
+	/**
+	 * Point to the test descriptor itself
+	 */
+	SELF,
+
+	/**
+	 * Skip the test descriptor itself and apply annotation {@link ResourceLock} to all its children
+	 */
+	CHILDREN
+
+}

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/JupiterTestDescriptor.java

@@ -33,6 +33,7 @@
 import org.junit.jupiter.api.parallel.Execution;
 import org.junit.jupiter.api.parallel.ResourceAccessMode;
 import org.junit.jupiter.api.parallel.ResourceLock;
+import org.junit.jupiter.api.parallel.ResourceLockTarget;
 import org.junit.jupiter.engine.config.JupiterConfiguration;
 import org.junit.jupiter.engine.execution.ConditionEvaluator;
 import org.junit.jupiter.engine.execution.JupiterEngineExecutionContext;
@@ -49,6 +50,7 @@
 import org.junit.platform.engine.support.descriptor.AbstractTestDescriptor;
 import org.junit.platform.engine.support.hierarchical.ExclusiveResource;
 import org.junit.platform.engine.support.hierarchical.ExclusiveResource.LockMode;
+import org.junit.platform.engine.support.hierarchical.ExclusiveResource.LockScope;
 import org.junit.platform.engine.support.hierarchical.Node;
 
 /**
@@ -183,7 +185,11 @@ public static ExecutionMode toExecutionMode(org.junit.jupiter.api.parallel.Execu
 	Set<ExclusiveResource> getExclusiveResourcesFromAnnotation(AnnotatedElement element) {
 		// @formatter:off
 		return findRepeatableAnnotations(element, ResourceLock.class).stream()
-				.map(resource -> new ExclusiveResource(resource.value(), toLockMode(resource.mode())))
+				.map(resource -> new ExclusiveResource(
+						resource.value(),
+						toLockMode(resource.mode()),
+						toLockScope(resource.target()))
+				)
 				.collect(toSet());
 		// @formatter:on
 	}
@@ -198,6 +204,16 @@ private static LockMode toLockMode(ResourceAccessMode mode) {
 		throw new JUnitException("Unknown ResourceAccessMode: " + mode);
 	}
 
+	private static LockScope toLockScope(ResourceLockTarget lockTarget) {
+		switch (lockTarget) {
+			case SELF:
+				return LockScope.SELF;
+			case CHILDREN:
+				return LockScope.CHILDREN;
+		}
+		throw new JUnitException("Unknown ResourceLockTarget: " + lockTarget);
+	}
+
 	@Override
 	public SkipResult shouldBeSkipped(JupiterEngineExecutionContext context) throws Exception {
 		context.getThrowableCollector().assertEmpty();

junit-platform-engine/src/main/java/org/junit/platform/engine/support/hierarchical/ExclusiveResource.java

@@ -52,18 +52,34 @@ public class ExclusiveResource {
 
 	private final String key;
 	private final LockMode lockMode;
+	private final LockScope lockScope;
 	private int hash;
 
 	/**
-	 * Create a new {@code ExclusiveResource}.
+	 * Create a new {@code ExclusiveResource} with a default lock scope {@link LockScope#SELF}
 	 *
 	 * @param key the identifier of the resource; never {@code null} or blank
 	 * @param lockMode the lock mode to use to synchronize access to the
 	 * resource; never {@code null}
+	 *
 	 */
 	public ExclusiveResource(String key, LockMode lockMode) {
+		this(key, lockMode, LockScope.SELF);
+	}
+
+	/**
+	 * Create a new {@code ExclusiveResource}.
+	 *
+	 * @param key the identifier of the resource; never {@code null} or blank
+	 * @param lockMode the lock mode to use to synchronize access to the
+	 * resource; never {@code null}
+	 * @param lockScope the lock scope to use to synchronize access to the
+	 * resource; never {@code null}
+	 */
+	public ExclusiveResource(String key, LockMode lockMode, LockScope lockScope) {
 		this.key = Preconditions.notBlank(key, "key must not be blank");
 		this.lockMode = Preconditions.notNull(lockMode, "lockMode must not be null");
+		this.lockScope = Preconditions.notNull(lockScope, "lockScope must not be null");
 	}
 
 	/**
@@ -80,6 +96,13 @@ public LockMode getLockMode() {
 		return lockMode;
 	}
 
+	/**
+	 * Get the lock scope of this resource.
+	 */
+	public LockScope getLockScope() {
+		return lockScope;
+	}
+
 	@Override
 	public boolean equals(Object o) {
 		if (this == o) {
@@ -89,21 +112,26 @@ public boolean equals(Object o) {
 			return false;
 		}
 		ExclusiveResource that = (ExclusiveResource) o;
-		return Objects.equals(key, that.key) && lockMode == that.lockMode;
+		return Objects.equals(key, that.key) && lockMode == that.lockMode && lockScope == that.lockScope;
 	}
 
 	@Override
 	public int hashCode() {
 		int h = hash;
 		if (h == 0) {
-			h = hash = Objects.hash(key, lockMode);
+			h = hash = Objects.hash(key, lockMode, lockScope);
 		}
 		return h;
 	}
 
 	@Override
 	public String toString() {
-		return new ToStringBuilder(this).append("key", key).append("lockMode", lockMode).toString();
+		return new ToStringBuilder(this).append("key", key).append("lockMode", lockMode).append("lockScope",
+			lockScope).toString();
+	}
+
+	public ExclusiveResource convertToSelfTarget() {
+		return new ExclusiveResource(key, lockMode, LockScope.SELF);
 	}
 
 	/**
@@ -131,4 +159,21 @@ public enum LockMode {
 
 	}
 
+	/**
+	 * {@code LockTarget} defines the scope of the lock.
+	 */
+	public enum LockScope {
+
+		/**
+		 * Lock the resource for the node itself.
+		 */
+		SELF,
+
+		/**
+		 * Lock the resource for all children of the node. Bypass the node itself.
+		 */
+		CHILDREN
+
+	}
+
 }