How to use embedded MongoDB with SpringBoot v3.0.0?

Question

I'm trying to connect embedded mongodb and test it with MongoDbSpringIntegrationTest. The problem is that the identical code works with spring boot in 2.7.7 but doesn't work with spring boot in 3.0.0. The question is how can I enable embedded mongodb for spring boot tests in 3.0.0?

dependencies in pom.xml: `

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>de.flapdoodle.embed</groupId>
        <artifactId>de.flapdoodle.embed.mongo</artifactId>
        <version>3.5.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-mongodb</artifactId>
        <version>3.0.0</version>
    </dependency>
</dependencies>

`

application.properties: `

spring.data.mongodb.database=test
spring.data.mongodb.port=27017
spring.mongodb.embedded.version=4.0.2

MongoDbSpringIntegrationTest:

@DataMongoTest
@ExtendWith(SpringExtension.class)
public class MongoDbSpringIntegrationTest {
  @DisplayName("given object to save"
      + " when save object using MongoDB template"
      + " then object is saved")
  @Test
  public void test(@Autowired MongoTemplate mongoTemplate) {
    // given
    DBObject objectToSave = BasicDBObjectBuilder.start()
        .add("key", "value")
        .get();

    // when
    mongoTemplate.save(objectToSave, "collection");

    // then
    assertThat(mongoTemplate.findAll(DBObject.class, "collection")).extracting("key")
        .containsOnly("value");
  }
}

`

When I run this I get this error: org.springframework.dao.DataAccessResourceFailureException: Timed out after 30000 ms while waiting to connect. Client view of cluster state is {type=UNKNOWN, servers=[{address=localhost:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.ConnectException: Connection refused: no further information}}]

Answer 1

The embedded mongo dependency you are using has support for Spring boot 2.7.x integration. There's a new version for Spring boot 3.x. You should only need to make 2 changes to your project:

Embedded Mongo dependency

Your pom.xml currently has:

<dependency>
    <groupId>de.flapdoodle.embed</groupId>
    <artifactId>de.flapdoodle.embed.mongo</artifactId>
    <version>3.5.3</version>
    <scope>test</scope>
</dependency>

Change that to:

<dependency>
    <groupId>de.flapdoodle.embed</groupId>
    <artifactId>de.flapdoodle.embed.mongo.spring30x</artifactId>
    <version>4.5.2</version>
    <scope>test</scope>
</dependency>

Notice the artifactId is different. Also 4.5.2 is the latest version at the time of this answer, find the latest anytime on maven.

Mongo version configuration

Your application.properties currently has:

spring.mongodb.embedded.version=4.0.2

Change that to:

de.flapdoodle.mongodb.embedded.version=4.0.2

The mongo version config is now resolved from flapdoodle's namespace, not Spring's.