Register AutoConfigurations using fully qualified class name

Update `AbstractApplicationContextRunner` and `Configurations` to
allow registration of beans with a specific generated bean name. By
default, no name is generated, however, `AutoConfigurations` has been
updated to use bean names using the fully qualified class name.

The update brings `ApplicationContextRunners` closer the behavior of
a standard Spring Boot application where user `@Configuration` classes
are usually registered with a simple name and auto-configurations are
imported (via an `ImportSelector`) using a fully qualified name.

Fixes gh-17963

Co-authored-by: Stéphane Nicoll <stephane.nicoll@broadcom.com>
Co-authored-by: Andy Wilkinson <andy.wilkinson@broadcom.com>
Co-authored-by: Dmytro Nosan <dimanosan@gmail.com>

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/context/runner/AbstractApplicationContextRunner.java

@@ -19,6 +19,7 @@ package org.springframework.boot.test.context.runner;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -27,6 +28,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinitionCustomizer;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.boot.context.annotation.Configurations;
@@ -38,12 +40,14 @@ import org.springframework.boot.test.util.TestPropertyValues;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextInitializer;
 import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.AnnotatedBeanDefinitionReader;
 import org.springframework.context.annotation.AnnotationConfigRegistry;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.env.Environment;
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
 
 /**
  * Utility design to run an {@link ApplicationContext} and provide AssertJ style
@@ -439,15 +443,27 @@ public abstract class AbstractApplicationContextRunner<SELF extends AbstractAppl
 		this.runnerConfiguration.environmentProperties.applyTo(context);
 		this.runnerConfiguration.beanRegistrations.forEach((registration) -> registration.apply(context));
 		this.runnerConfiguration.initializers.forEach((initializer) -> initializer.initialize(context));
-		Class<?>[] classes = Configurations.getClasses(this.runnerConfiguration.configurations);
-		if (classes.length > 0) {
-			((AnnotationConfigRegistry) context).register(classes);
+		if (!CollectionUtils.isEmpty(this.runnerConfiguration.configurations)) {
+			BiConsumer<Class<?>, String> registrar = getRegistrar(context);
+			for (Configurations configurations : Configurations.collate(this.runnerConfiguration.configurations)) {
+				for (Class<?> beanClass : Configurations.getClasses(configurations)) {
+					String beanName = configurations.getBeanName(beanClass);
+					registrar.accept(beanClass, beanName);
+				}
+			}
 		}
 		if (refresh) {
 			context.refresh();
 		}
 	}
 
+	private BiConsumer<Class<?>, String> getRegistrar(C context) {
+		if (context instanceof BeanDefinitionRegistry registry) {
+			return new AnnotatedBeanDefinitionReader(registry, context.getEnvironment())::registerBean;
+		}
+		return (beanClass, beanName) -> ((AnnotationConfigRegistry) context).register(beanClass);
+	}
+
 	private void accept(ContextConsumer<? super A> consumer, A context) {
 		try {
 			consumer.accept(context);

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/example/duplicate/first/EmptyConfig.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2012-2024 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.boot.test.context.example.duplicate.first;
+
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Example configuration to showcase handing of duplicate class names.
+ *
+ * @author Stephane Nicoll
+ */
+@Configuration
+public class EmptyConfig {
+
+}

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/example/duplicate/second/EmptyConfig.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2012-2024 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.boot.test.context.example.duplicate.second;
+
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Example configuration to showcase handing of duplicate class names.
+ *
+ * @author Stephane Nicoll
+ */
+@Configuration
+public class EmptyConfig {
+
+}

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/runner/AbstractApplicationContextRunnerTests.java

@@ -17,6 +17,9 @@
 package org.springframework.boot.test.context.runner;
 
 import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -27,6 +30,8 @@ import org.springframework.beans.factory.BeanCurrentlyInCreationException;
 import org.springframework.beans.factory.BeanDefinitionStoreException;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.support.BeanDefinitionOverrideException;
+import org.springframework.boot.context.annotation.Configurations;
 import org.springframework.boot.context.annotation.UserConfigurations;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -139,6 +144,38 @@ abstract class AbstractApplicationContextRunnerTests<T extends AbstractApplicati
 		get().withUserConfiguration(FooConfig.class).run((context) -> assertThat(context).hasBean("foo"));
 	}
 
+	@Test
+	void runWithUserConfigurationsRegistersDefaultBeanName() {
+		get().withUserConfiguration(FooConfig.class)
+			.run((context) -> assertThat(context).hasBean("abstractApplicationContextRunnerTests.FooConfig"));
+	}
+
+	@Test
+	void runWithUserConfigurationsWhenHasSameShortClassNamedRegistersWithoutBeanName() {
+		get()
+			.withUserConfiguration(org.springframework.boot.test.context.example.duplicate.first.EmptyConfig.class,
+					org.springframework.boot.test.context.example.duplicate.second.EmptyConfig.class)
+			.run((context) -> assertThat(context.getStartupFailure())
+				.isInstanceOf(BeanDefinitionOverrideException.class));
+	}
+
+	@Test
+	void runFullyQualifiedNameConfigurationsRegistersFullyQualifiedBeanName() {
+		get().withConfiguration(FullyQualifiedNameConfigurations.of(FooConfig.class))
+			.run((context) -> assertThat(context).hasBean(FooConfig.class.getName()));
+	}
+
+	@Test
+	void runWithFullyQualifiedNameConfigurationsWhenHasSameShortClassNamedRegistersWithFullyQualifiedBeanName() {
+		get()
+			.withConfiguration(FullyQualifiedNameConfigurations.of(
+					org.springframework.boot.test.context.example.duplicate.first.EmptyConfig.class,
+					org.springframework.boot.test.context.example.duplicate.second.EmptyConfig.class))
+			.run((context) -> assertThat(context)
+				.hasSingleBean(org.springframework.boot.test.context.example.duplicate.first.EmptyConfig.class)
+				.hasSingleBean(org.springframework.boot.test.context.example.duplicate.second.EmptyConfig.class));
+	}
+
 	@Test
 	void runWithUserNamedBeanShouldRegisterBean() {
 		get().withBean("foo", String.class, () -> "foo").run((context) -> assertThat(context).hasBean("foo"));
@@ -384,4 +421,21 @@ abstract class AbstractApplicationContextRunnerTests<T extends AbstractApplicati
 
 	}
 
+	static class FullyQualifiedNameConfigurations extends Configurations {
+
+		protected FullyQualifiedNameConfigurations(Collection<Class<?>> classes) {
+			super(null, classes, Class::getName);
+		}
+
+		@Override
+		protected Configurations merge(Set<Class<?>> mergedClasses) {
+			return new FullyQualifiedNameConfigurations(mergedClasses);
+		}
+
+		static FullyQualifiedNameConfigurations of(Class<?>... classes) {
+			return new FullyQualifiedNameConfigurations(List.of(classes));
+		}
+
+	}
+
 }