testCompile('de.flapdoodle.embed:de.flapdoodle.embed.mongo:1.46.0')

package com.example.springDemo;

import com.mongodb.DB;
import com.mongodb.MongoClient;
import de.flapdoodle.embed.mongo.MongodExecutable;
import de.flapdoodle.embed.mongo.MongodProcess;
import de.flapdoodle.embed.mongo.MongodStarter;
import de.flapdoodle.embed.mongo.config.MongodConfigBuilder;
import de.flapdoodle.embed.mongo.config.Net;
import de.flapdoodle.embed.mongo.distribution.Version;
import de.flapdoodle.embed.process.runtime.Network;
import org.junit.After;
import org.junit.Before;


public class MongodbBaseTest {
    private static final MongodStarter starter = MongodStarter.getDefaultInstance();
    protected MongoClient mongo;
    protected DB db;
    private MongodExecutable mongodExecutable;
    private MongodProcess mongod;

    @Before
    public void setUp() throws Exception {
        mongodExecutable = starter.prepare(new MongodConfigBuilder()
                .version(Version.Main.PRODUCTION)
                .net(new Net(12345, Network.localhostIsIPv6())).build());
        mongod = mongodExecutable.start();


        mongo = new MongoClient("localhost", 12345);
        db = mongo.getDB("embedded-mongo");
    }

    @After
    public void tearDown() throws Exception {
        mongod.stop();
        mongodExecutable.stop();
    }
}

package com.example.springDemo;

import com.mongodb.BasicDBObject;
import com.mongodb.BasicDBObjectBuilder;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import org.junit.Before;
import org.junit.Test;
import static org.junit.Assert.assertThat;
import static org.hamcrest.CoreMatchers.is;
public class UserTest extends MongodbBaseTest {
    private DBCollection users;

    @Override
    @Before
    public void setUp() throws Exception {
        super.setUp();
        users = db.getCollection("users");
    }

    @Test
    public void should_insert_and_get_user() {
        final DBObject userDocument = new BasicDBObjectBuilder()
                .add("name", "lind")
                .get();
        users.insert(userDocument);

        final DBObject userDocumentFromDb = users.findOne(new BasicDBObject("_id", userDocument.get("_id")));

        assertThat(userDocumentFromDb.get("name"), is("lind"));
    }
}