Register runtime hints for @⁠TestBean fully-qualified method names

This commit introduces a TestBeanReflectiveProcessor that registers
GraalVM native image reflection hints for a fully-qualified method name
configured via @⁠TestBean.

Closes gh-33836

spring-test/src/main/java/org/springframework/test/context/bean/override/convention/TestBean.java

@@ -22,6 +22,7 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.aot.hint.annotation.Reflective;
 import org.springframework.core.annotation.AliasFor;
 import org.springframework.test.context.bean.override.BeanOverride;
 
@@ -115,6 +116,7 @@ import org.springframework.test.context.bean.override.BeanOverride;
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 @BeanOverride(TestBeanOverrideProcessor.class)
+@Reflective(TestBeanReflectiveProcessor.class)
 public @interface TestBean {
 
 	/**

spring-test/src/main/java/org/springframework/test/context/bean/override/convention/TestBeanReflectiveProcessor.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.test.context.bean.override.convention;
+
+import java.lang.reflect.AnnotatedElement;
+import java.util.List;
+
+import org.springframework.aot.hint.ReflectionHints;
+import org.springframework.aot.hint.TypeReference;
+import org.springframework.aot.hint.annotation.ReflectiveProcessor;
+import org.springframework.core.annotation.MergedAnnotation;
+import org.springframework.core.annotation.MergedAnnotations;
+import org.springframework.util.Assert;
+
+import static org.springframework.aot.hint.ExecutableMode.INVOKE;
+
+/**
+ * {@link ReflectiveProcessor} that processes {@link TestBean @TestBean} annotations.
+ *
+ * @author Sam Brannen
+ * @since 6.2
+ */
+class TestBeanReflectiveProcessor implements ReflectiveProcessor {
+
+	@Override
+	public void registerReflectionHints(ReflectionHints hints, AnnotatedElement element) {
+		MergedAnnotations.from(element)
+				.get(TestBean.class)
+				.synthesize(MergedAnnotation::isPresent)
+				.map(TestBean::methodName)
+				.filter(methodName -> methodName.contains("#"))
+				.ifPresent(methodName -> {
+					int indexOfHash = methodName.lastIndexOf('#');
+					String className = methodName.substring(0, indexOfHash).trim();
+					Assert.hasText(className, () -> "No class name present in fully-qualified method name: " + methodName);
+					String methodNameToUse = methodName.substring(indexOfHash + 1).trim();
+					Assert.hasText(methodNameToUse, () -> "No method name present in fully-qualified method name: " + methodName);
+					hints.registerType(TypeReference.of(className), builder ->
+							builder.withMethod(methodNameToUse, List.of(), INVOKE));
+				});
+	}
+
+}