Merge pull request #44187 from thecooldrop

* pr/44187:
  Polish 'Document methods of starting Testcontainer containers'
  Document methods of starting Testcontainer containers

Closes gh-44187

buildSrc/src/main/resources/org/springframework/boot/build/antora/antora-asciidoc-attributes.properties

@@ -75,6 +75,7 @@ url-spring-data-rest-docs=https://docs.spring.io/spring-data/rest/reference/{ant
 url-spring-data-rest-site=https://spring.io/projects/spring-data-rest
 url-spring-data-rest-javadoc=https://docs.spring.io/spring-data/rest/docs/{dotxversion-spring-data-rest}/api
 url-spring-data-site=https://spring.io/projects/spring-data
+url-testcontainers-docs=https://java.testcontainers.org
 url-testcontainers-activemq-javadoc=https://javadoc.io/doc/org.testcontainers/activemq/{version-testcontainers-activemq}
 url-testcontainers-cassandra-javadoc=https://javadoc.io/doc/org.testcontainers/cassandra/{version-testcontainers-cassandra}
 url-testcontainers-couchbase-javadoc=https://javadoc.io/doc/org.testcontainers/couchbase/{version-testcontainers-couchbase}

spring-boot-project/spring-boot-docs/src/docs/antora/modules/reference/pages/testing/testcontainers.adoc

@@ -5,12 +5,93 @@ The https://www.testcontainers.org/[Testcontainers] library provides a way to ma
 It integrates with JUnit, allowing you to write a test class that can start up a container before any of the tests run.
 Testcontainers is especially useful for writing integration tests that talk to a real backend service such as MySQL, MongoDB, Cassandra and others.
 
-Testcontainers can be used in a Spring Boot test as follows:
+In following sections we will describe some of the methods you can use to integrate Testcontainers with your tests.
 
-include-code::vanilla/MyIntegrationTests[]
 
-This will start up a docker container running Neo4j (if Docker is running locally) before any of the tests are run.
-In most cases, you will need to configure the application to connect to the service running in the container.
+[[testing.testcontainers.spring-beans]]
+== Using Spring Beans
+
+The containers provided by Testcontainers can be managed by Spring Boot as beans.
+
+To declare a container as a bean, add a javadoc:org.springframework.context.annotation.Bean[format=annotation] method to your test configuration:
+
+include-code::MyTestConfiguration[]
+
+You can then inject and use the container by importing the configuration class in the test class:
+
+include-code::MyIntegrationTests[]
+
+TIP: This method of managing containers is often used in combination with xref:#testing.testcontainers.service-connections[service connection annotations].
+
+
+
+[[testing.testcontainers.junit-extension]]
+== Using the JUnit Extension
+
+Testcontainers provides a JUnit extension which can be used to manage containers in your tests.
+The extension is activated by applying the javadoc:org.testcontainers.junit.jupiter.Testcontainers[format=annotation] annotation from Testcontainers to your test class.
+
+You can then use the javadoc:org.testcontainers.junit.jupiter.Container[format=annotation] annotation on static container fields.
+
+The javadoc:org.testcontainers.junit.jupiter.Testcontainers[format=annotation] annotation can be used on vanilla JUnit tests, or in combination with javadoc:org.springframework.boot.test.context.SpringBootTest[format=annotation]:
+
+include-code::MyIntegrationTests[]
+
+The example above will start up a Neo4j container before any of the tests are run.
+The lifecycle of the container instance is managed by Testcontainers, as described in {url-testcontainers-docs}/test_framework_integration/junit_5/#extension[their official documentation].
+
+NOTE: In most cases, you will additionally need to configure the application to connect to the service running in the container.
+
+
+
+[[testing.testcontainers.importing-configuration-interfaces]]
+== Importing Container Configuration Interfaces
+
+A common pattern with Testcontainers is to declare the container instances as static fields in an interface.
+
+For example, the following interface declares two containers, one named `mongo` of type javadoc:org.testcontainers.containers.MongoDBContainer[] and another named `neo4j` of type javadoc:org.testcontainers.containers.Neo4jContainer.Neo4jContainer[]:
+
+include-code::MyContainers[]
+
+When you have containers declared in this way, you can reuse their configuration in multiple tests by having the test classes implement the interface.
+
+It's also possible to use the same interface configuration in your Spring Boot tests.
+To do so, add javadoc:org.springframework.boot.testcontainers.context.ImportTestcontainers[format=annotation] to your test configuration class:
+
+include-code::MyTestConfiguration[]
+
+
+
+[[testing.testcontainers.lifecycle]]
+== Lifecycle of Managed Containers
+
+If you have used the annotations and extensions provided by Testcontainers, then the lifecycle of container instances is managed entirely by Testcontainers.
+Please refer to the {url-testcontainers-docs}[offical Testcontainers documentation] for the information.
+
+When the containers are managed by Spring as beans, then their lifecycle is managed by Spring:
+
+* Container beans are created and started before all other beans.
+
+* Container beans are stopped after the destruction of all other beans.
+
+This process ensures that any beans, which rely on functionality provided by the containers, can use those functionalities.
+It also ensures that they are cleaned up whilst the container is still available.
+
+TIP: When your application beans rely on functionality of containers, prefer configuring the containers as Spring beans to ensure the correct lifecycle behavior.
+
+NOTE: Having containers managed by Testcontainers instead of as Spring beans provides no guarantee of the order in which beans and containers will shutdown.
+It can happen that containers are shutdown before the beans relying on container functionality are cleaned up.
+This can lead to exceptions being thrown by client beans, for example, due to loss of connection.
+
+Container beans are created and started once per application context managed by Spring's TestContext Framework.
+For details about how TestContext Framework manages the underlying application contexts and beans therein, please refer to the {url-spring-framework-docs}[Spring Framework documentation].
+
+Container beans are stopped as part of the TestContext Framework's standard application context shutdown process.
+When the application context gets shutdown, the containers are shutdown as well.
+This usually happens after all tests using that specific cached application context have finished executing.
+It may also happen earlier, depending on the caching behavior configured in TestContext Framework.
+
+NOTE: A single test container instance can, and often is, retained across execution of tests from multiple test classes.
 
 
 

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/testing/testcontainers/importingconfigurationinterfaces/MyContainers.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.importingconfigurationinterfaces;
+
+import org.testcontainers.containers.MongoDBContainer;
+import org.testcontainers.containers.Neo4jContainer;
+import org.testcontainers.junit.jupiter.Container;
+
+interface MyContainers {
+
+	@Container
+	MongoDBContainer mongoContainer = new MongoDBContainer("mongo:5.0");
+
+	@Container
+	Neo4jContainer<?> neo4jContainer = new Neo4jContainer<>("neo4j:5");
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/testing/testcontainers/importingconfigurationinterfaces/MyTestConfiguration.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.importingconfigurationinterfaces;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.boot.testcontainers.context.ImportTestcontainers;
+
+@TestConfiguration(proxyBeanMethods = false)
+@ImportTestcontainers(MyContainers.class)
+class MyTestConfiguration {
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/testing/testcontainers/junitextension/MyIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.docs.testing.testcontainers.vanilla;
+package org.springframework.boot.docs.testing.testcontainers.junitextension;
 
 import org.junit.jupiter.api.Test;
 import org.testcontainers.containers.Neo4jContainer;
@@ -32,7 +32,7 @@ class MyIntegrationTests {
 
 	@Test
 	void myTest() {
-		// ...
+		/**/ System.out.println(neo4j);
 	}
 
 }

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/testing/testcontainers/serviceconnections/MyIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -34,7 +34,7 @@ class MyIntegrationTests {
 
 	@Test
 	void myTest() {
-		// ...
+		/**/ System.out.println(neo4j);
 	}
 
 }

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/testing/testcontainers/springbeans/MyIntegrationTests.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.springbeans;
+
+import org.junit.jupiter.api.Test;
+import org.testcontainers.containers.MongoDBContainer;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Import;
+
+@SpringBootTest
+@Import(MyTestConfiguration.class)
+class MyIntegrationTests {
+
+	@Autowired
+	private MongoDBContainer mongo;
+
+	@Test
+	void myTest() {
+		/**/ System.out.println(this.mongo);
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/testing/testcontainers/springbeans/MyTestConfiguration.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.springbeans;
+
+import org.testcontainers.containers.MongoDBContainer;
+import org.testcontainers.utility.DockerImageName;
+
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.Bean;
+
+@TestConfiguration(proxyBeanMethods = false)
+class MyTestConfiguration {
+
+	@Bean
+	MongoDBContainer mongoDbContainer() {
+		return new MongoDBContainer(DockerImageName.parse("mongo:5.0"));
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/dynamicproperties/MyIntegrationTests.kt

@@ -29,7 +29,7 @@ class MyIntegrationTests {
 
 	@Test
 	fun myTest() {
-		// ...
+		/**/ println()
 	}
 
 	companion object {

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/importingconfigurationinterfaces/MyContainers.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.importingconfigurationinterfaces
+
+import org.testcontainers.containers.MongoDBContainer
+import org.testcontainers.containers.Neo4jContainer
+import org.testcontainers.junit.jupiter.Container
+
+interface MyContainers {
+
+	companion object {
+
+		@Container
+		val mongoContainer: MongoDBContainer = MongoDBContainer("mongo:5.0")
+
+		@Container
+		val neo4jContainer: Neo4jContainer<*> = Neo4jContainer("neo4j:5")
+
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/importingconfigurationinterfaces/MyTestConfiguration.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.importingconfigurationinterfaces
+
+import org.springframework.boot.test.context.TestConfiguration
+import org.springframework.boot.testcontainers.context.ImportTestcontainers
+
+@TestConfiguration(proxyBeanMethods = false)
+@ImportTestcontainers(MyContainers::class)
+class MyTestConfiguration {
+
+}

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/junitextension/MyIntegrationTests.kt

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.docs.testing.testcontainers.vanilla
+package org.springframework.boot.docs.testing.testcontainers.junitextension
 
 import org.junit.jupiter.api.Test;
 import org.testcontainers.containers.Neo4jContainer;
@@ -22,7 +22,6 @@ import org.testcontainers.junit.jupiter.Container;
 import org.testcontainers.junit.jupiter.Testcontainers;
 
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.boot.testcontainers.service.connection.ServiceConnection
 
 @Testcontainers
 @SpringBootTest
@@ -30,13 +29,15 @@ class MyIntegrationTests {
 
 	@Test
 	fun myTest() {
-		// ...
+		/**/ println()
 	}
 
 	companion object {
+
 		@Container
 		@JvmStatic
 		val neo4j = Neo4jContainer("neo4j:5");
+
 	}
 }
 

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/serviceconnections/MyIntegrationTests.kt

@@ -30,7 +30,7 @@ class MyIntegrationTests {
 
 	@Test
 	fun myTest() {
-		// ...
+		/**/ println()
 	}
 
 	companion object {

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/serviceconnections/MyRedisConfiguration.kt

@@ -23,9 +23,11 @@ import org.testcontainers.containers.GenericContainer
 
 @TestConfiguration(proxyBeanMethods = false)
 class MyRedisConfiguration {
+
 	@Bean
 	@ServiceConnection(name = "redis")
 	fun redisContainer(): GenericContainer<*> {
 		return GenericContainer("redis:7")
 	}
+
 }

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/springbeans/MyIntegrationTests.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.springbeans
+
+import org.junit.jupiter.api.Test
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.context.annotation.Import
+import org.testcontainers.containers.MongoDBContainer
+
+@SpringBootTest
+@Import(MyTestConfiguration::class)
+class MyIntegrationTests {
+
+	@Autowired
+	private val mongo: MongoDBContainer? = null
+
+	@Test
+	fun myTest() {
+		/**/ println()
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/testing/testcontainers/springbeans/MyTestConfiguration.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012-2025 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.docs.testing.testcontainers.springbeans
+
+import org.springframework.boot.test.context.TestConfiguration
+import org.springframework.context.annotation.Bean
+import org.testcontainers.containers.MongoDBContainer
+import org.testcontainers.utility.DockerImageName
+
+@TestConfiguration(proxyBeanMethods = false)
+class MyTestConfiguration {
+
+	@Bean
+	fun mongoDbContainer(): MongoDBContainer {
+		return MongoDBContainer(DockerImageName.parse("mongo:5.0"))
+	}
+
+}

src/checkstyle/checkstyle-suppressions.xml

@@ -82,6 +82,7 @@
 	<suppress files="spring-boot-configuration-processor[\\/]src[\\/]test[\\/]java[\\/]org[\\/]springframework[\\/]boot[\\/]configurationsample[\\/]" checks="SpringDeprecatedCheck"/>
 	<suppress files="ImportTestcontainersTests\.java" checks="InterfaceIsType" />
 	<suppress files="MyContainers\.java" checks="InterfaceIsType" />
+	<suppress files="MyInterface\.java" checks="InterfaceIsType" />
 	<suppress files="SpringBootBanner\.java" checks="SpringLeadingWhitespace" />
 	<suppress files="LoadTimeWeaverAwareConsumerContainers\.java" checks="InterfaceIsType" />
 </suppressions>