Replace Flapdoodle with Testcontainers for MongoDB support.

For more details on this usage of Testcontainers, see https://bsideup.github.io/posts/local_development_with_testcontainers/

Related issues: https://github.com/spring-projects/spring-boot/issues/30863

spring-session-samples/spring-session-sample-boot-mongodb-reactive/spring-session-sample-boot-mongodb-reactive.gradle

@@ -5,7 +5,7 @@ dependencies {
 	implementation  "org.springframework.boot:spring-boot-starter-webflux"
 	implementation  "org.springframework.boot:spring-boot-starter-thymeleaf"
 	implementation  "org.springframework.boot:spring-boot-starter-data-mongodb-reactive"
-	implementation  "de.flapdoodle.embed:de.flapdoodle.embed.mongo"
+    implementation  "org.testcontainers:mongodb"
 
 	testImplementation "org.springframework.boot:spring-boot-starter-test"
 	testImplementation "org.seleniumhq.selenium:htmlunit-driver"

spring-session-samples/spring-session-sample-boot-mongodb-reactive/src/main/java/org/springframework/session/mongodb/examples/SpringSessionMongoReactiveApplication.java

@@ -18,7 +18,16 @@ package org.springframework.session.mongodb.examples;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
 import org.springframework.session.data.mongo.config.annotation.web.reactive.EnableMongoWebSession;
+import org.testcontainers.containers.MongoDBContainer;
+import org.testcontainers.utility.DockerImageName;
+
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * Pure Spring-based application (using Spring Boot for dependency management), hence no
@@ -31,8 +40,35 @@ import org.springframework.session.data.mongo.config.annotation.web.reactive.Ena
 @EnableMongoWebSession
 public class SpringSessionMongoReactiveApplication {
 
-	public static void main(String[] args) {
-		SpringApplication.run(SpringSessionMongoReactiveApplication.class);
+	/**
+	 * Use Testcontainers to managed MongoDB through Docker.
+	 * <p>
+	 * @see https://bsideup.github.io/posts/local_development_with_testcontainers/
+	 */
+	static class Initializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
+
+		static MongoDBContainer mongo = new MongoDBContainer(DockerImageName.parse("mongo:5.0"));
+
+		public static Map<String, String> getProperties() {
+			mongo.start();
+
+			HashMap<String, String> properties = new HashMap<>();
+			properties.put("spring.data.mongodb.host", mongo.getHost());
+			properties.put("spring.data.mongodb.port", mongo.getFirstMappedPort() + "");
+			return properties;
+		}
+
+		@Override
+		public void initialize(ConfigurableApplicationContext context) {
+			ConfigurableEnvironment env = context.getEnvironment();
+			env.getPropertySources().addFirst(new MapPropertySource("testcontainers", (Map) getProperties()));
+		}
 	}
 
+
+	public static void main(String[] args) {
+		SpringApplication application = new SpringApplication(SpringSessionMongoReactiveApplication.class);
+		application.addInitializers(new Initializer());
+		application.run(args);
+	}
 }

spring-session-samples/spring-session-sample-boot-mongodb-reactive/src/main/resources/application.properties

@@ -0,0 +1,2 @@
+logging.level.org.springframework.data.mongodb=DEBUG
+logging.level.org.springframework.session=DEBUG

spring-session-samples/spring-session-sample-boot-mongodb-reactive/src/main/resources/application.yml

@@ -1,8 +0,0 @@
-logging:
-  level:
-    org.springframework.data.mongodb: DEBUG
-    org.springframework.session: DEBUG
-spring:
-  mongodb:
-    embedded:
-      version: 3.4.3

spring-session-samples/spring-session-sample-boot-mongodb-reactive/src/test/java/org/springframework/session/mongodb/examples/AttributeTests.java

@@ -16,21 +16,21 @@
 
 package org.springframework.session.mongodb.examples;
 
-import java.util.List;
-
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.openqa.selenium.WebDriver;
 import org.openqa.selenium.htmlunit.HtmlUnitDriver;
-
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.web.server.LocalServerPort;
 import org.springframework.session.mongodb.examples.pages.HomePage;
 import org.springframework.session.mongodb.examples.pages.HomePage.Attribute;
+import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit.jupiter.SpringExtension;
 
+import java.util.List;
+
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
@@ -39,6 +39,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  */
 @ExtendWith(SpringExtension.class)
 @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+@ContextConfiguration(initializers = SpringSessionMongoReactiveApplication.Initializer.class)
 public class AttributeTests {
 
 	@LocalServerPort