Avoid hard dependency on Spring AOP for mock resolution

Closes gh-33774

Author: jhoeller

Diff for: spring-test/src/main/java/org/springframework/test/context/bean/override/mockito/MockitoSpyBeanOverrideHandler.java

@@ -70,19 +70,22 @@ protected Object createOverrideInstance(String beanName, @Nullable BeanDefinitio
 		return createSpy(beanName, existingBeanInstance);
 	}
 
-	@SuppressWarnings("unchecked")
 	private Object createSpy(String name, Object instance) {
 		Class<?> resolvedTypeToOverride = getBeanType().resolve();
 		Assert.notNull(resolvedTypeToOverride, "Failed to resolve type to override");
 		Assert.isInstanceOf(resolvedTypeToOverride, instance);
 		if (Mockito.mockingDetails(instance).isSpy()) {
 			return instance;
 		}
+
 		MockSettings settings = MockReset.withSettings(getReset());
 		if (StringUtils.hasLength(name)) {
 			settings.name(name);
 		}
-		settings.verificationStartedListeners(verificationStartedListener);
+		if (SpringMockResolver.aopAvailable) {
+			settings.verificationStartedListeners(verificationStartedListener);
+		}
+
 		Class<?> toSpy;
 		if (Proxy.isProxyClass(instance.getClass())) {
 			settings.defaultAnswer(AdditionalAnswers.delegatesTo(instance));

Diff for: spring-test/src/main/java/org/springframework/test/context/bean/override/mockito/SpringMockResolver.java

@@ -22,6 +22,7 @@
 import org.springframework.aop.framework.Advised;
 import org.springframework.aop.support.AopUtils;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 
 /**
  * A {@link MockResolver} for testing Spring applications with Mockito.
@@ -31,30 +32,35 @@
  *
  * @author Sam Brannen
  * @author Andy Wilkinson
+ * @author Juergen Hoeller
  * @since 6.2
  */
 public class SpringMockResolver implements MockResolver {
 
+	static final boolean aopAvailable = ClassUtils.isPresent(
+			"org.springframework.aop.framework.Advised", SpringMockResolver.class.getClassLoader());
+
+
 	@Override
 	public Object resolve(Object instance) {
-		return getUltimateTargetObject(instance);
+		if (aopAvailable) {
+			return getUltimateTargetObject(instance);
+		}
+		return instance;
 	}
 
 	/**
 	 * This is a modified version of
 	 * {@link org.springframework.test.util.AopTestUtils#getUltimateTargetObject(Object)
-	 * AopTestUtils#getUltimateTargetObject()} which only checks static target
-	 * sources.
-	 * @param <T> the type of the target object
+	 * AopTestUtils#getUltimateTargetObject()} which only checks static target sources.
 	 * @param candidate the instance to check (potentially a Spring AOP proxy;
 	 * never {@code null})
 	 * @return the target object or the {@code candidate} (never {@code null})
 	 * @throws IllegalStateException if an error occurs while unwrapping a proxy
 	 * @see Advised#getTargetSource()
 	 * @see TargetSource#isStatic()
 	 */
-	@SuppressWarnings("unchecked")
-	static <T> T getUltimateTargetObject(Object candidate) {
+	static Object getUltimateTargetObject(Object candidate) {
 		Assert.notNull(candidate, "Candidate must not be null");
 		try {
 			if (AopUtils.isAopProxy(candidate) && candidate instanceof Advised advised) {
@@ -70,7 +76,7 @@ static <T> T getUltimateTargetObject(Object candidate) {
 		catch (Throwable ex) {
 			throw new IllegalStateException("Failed to unwrap proxied object", ex);
 		}
-		return (T) candidate;
+		return candidate;
 	}
 
 }