Improve nullReturningBeanPostProcessor() test

See gh-28459

spring-context/src/test/java/org/springframework/context/annotation/AnnotationConfigApplicationContextTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -148,25 +148,53 @@ class AnnotationConfigApplicationContextTests {
 	void nullReturningBeanPostProcessor() {
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 		context.register(AutowiredConfig.class);
+		// 1st BPP always gets invoked
+		context.getBeanFactory().addBeanPostProcessor(new BeanPostProcessor() {
+			@Override
+			public Object postProcessBeforeInitialization(Object bean, String beanName) {
+				if (bean instanceof TestBean) {
+					TestBean testBean = (TestBean) bean;
+					testBean.name = testBean.name + "-before";
+				}
+				return bean;
+			}
+			@Override
+			public Object postProcessAfterInitialization(Object bean, String beanName) {
+				if (bean instanceof TestBean) {
+					TestBean testBean = (TestBean) bean;
+					testBean.name = testBean.name + "-after";
+				}
+				return bean;
+			}
+		});
+		// 2nd BPP always returns null for a TestBean
 		context.getBeanFactory().addBeanPostProcessor(new BeanPostProcessor() {
 			@Override
 			public Object postProcessBeforeInitialization(Object bean, String beanName) {
 				return (bean instanceof TestBean ? null : bean);
 			}
+			@Override
+			public Object postProcessAfterInitialization(Object bean, String beanName) {
+				return (bean instanceof TestBean ? null : bean);
+			}
 		});
+		// 3rd BPP never gets invoked with a TestBean
 		context.getBeanFactory().addBeanPostProcessor(new BeanPostProcessor() {
 			@Override
 			public Object postProcessBeforeInitialization(Object bean, String beanName) {
-				bean.getClass().getName();
+				assertThat(bean).isNotInstanceOf(TestBean.class);
 				return bean;
 			}
 			@Override
 			public Object postProcessAfterInitialization(Object bean, String beanName) {
-				bean.getClass().getName();
+				assertThat(bean).isNotInstanceOf(TestBean.class);
 				return bean;
 			}
 		});
 		context.refresh();
+		TestBean testBean = context.getBean(TestBean.class);
+		assertThat(testBean).isNotNull();
+		assertThat(testBean.name).isEqualTo("foo-before-after");
 	}
 
 	@Test