You don't need this for Spring Boot >= 1.5.x, it's included now in Spring Boot itself, see: 41.3.10 Auto-configured Data MongoDB tests

Provides a @DataMongoTest for the automatic configuration of tests with Spring Boot 1.4+.

Note: I have proposed this as a PR for Spring Boot itself: Provide a @DataMongoTest similar to @DataJpaTest

Spring Boot 1.4 brought a new feature called Auto-configured tests.

Thoses "slices" can be used when starting a full application auto-configuration is overkill for a specific tests.

The reference documentation has chapter on how to use them.

Stéphane Nicoll created a nice post on how to create your own slice, called Custom test slice with Spring Boot 1.4.

@DataMongoTest uses his work to provide a custom test slice that works with pretty much the same way for Spring Data MongoDB as @DataJpaTest does for Spring Data JPA.

Add

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>
 <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>eu.michael-simons</groupId>
    <artifactId>datamongotest-autoconfigure-spring-boot</artifactId>
    <version>0.0.1</version>
    <scope>test</scope>
</dependency>

to your dependencies, create and write your MongoDB repositories in your Spring Boot Application as you did before.

Annotate your test with @DataMongoTest and benefit from a MongoTemplate and all your repositories:

@RunWith(SpringRunner.class)
@DataMongoTest
public class DataMongoSampleTests {

    @Autowired
    private MongoTemplate mongoTemplate;
    
    @Autowired
    private TweetRepository tweetRepository;

    @Test
    public void testStuff() {
        TweetDocument tweet = new TweetDocument();
        tweet.setText("Look, new @DataMongoTest!");
        
        tweet = this.tweetRepository.save(tweet);
        assertThat(tweet.getId(), notNullValue());
        
        assertTrue(this.mongoTemplate.collectionExists("tweets"));
    }
}

The automatic configuration takes your application.properties into account. Make sure you configure another database connection for your test profile through

spring.data.mongodb.database = testdatabase

Or you might consider adding

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

to your test dependencies. This activates Spring Boot support for an embedded MongoDB process and you end up with an embedded Mongo connection like you do when using @DataJpaTest where you get an H2 embedded database.

If you don't want this and but have embedded Mongo on your path, consider adding

@AutoConfigureEmbeddedTestMongod(enabled = false)

to your test as well.