Add MongoDBDatabaseNameTest

modules/mongodb/build.gradle

@@ -1,7 +1,21 @@
+plugins {
+    id 'org.springframework.boot' version '2.3.1.RELEASE'
+    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
+}
+
 description = "Testcontainers :: MongoDB"
 
 dependencies {
     compile project(':testcontainers')
 
     testCompile("org.mongodb:mongodb-driver-sync:4.0.2")
+    testCompile("org.springframework.boot:spring-boot-starter")
+    testCompile("org.springframework.boot:spring-boot-starter-test") {
+        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
+    }
+    testCompile("org.springframework.data:spring-data-mongodb:3.0.1.RELEASE")
+}
+
+bootJar {
+    enabled = false
 }

modules/mongodb/src/test/java/org/testcontainers/containers/MongoDBDatabaseNameTest.java

@@ -0,0 +1,115 @@
+package org.testcontainers.containers;
+
+import com.mongodb.client.MongoClient;
+import com.mongodb.client.MongoClients;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
+import org.jetbrains.annotations.NotNull;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.test.autoconfigure.data.mongo.DataMongoTest;
+import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.util.Objects;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.stream.StreamSupport;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+@Slf4j
+@DataMongoTest
+@ContextConfiguration(initializers = MongoDBDatabaseNameTest.Initializer.class)
+@RunWith(SpringRunner.class)
+public class MongoDBDatabaseNameTest {
+    private static final MongoDBContainer MONGO_DB_CONTAINER = new MongoDBContainer();
+    private static final String DATABASE_NAME = "my-db";
+
+    @Autowired
+    private MongoTemplate mongoTemplate;
+
+    @BeforeClass
+    public static void setUpAll() {
+        MONGO_DB_CONTAINER.start();
+    }
+
+    @AfterClass
+    public static void tearDownAll() {
+        MONGO_DB_CONTAINER.stop();
+    }
+
+    @Test
+    public void shouldTestDatabaseName() {
+        //1. Database name was already set to the MongoTemplate during auto-config.
+        assertEquals(DATABASE_NAME, mongoTemplate.getDb().getName());
+
+        try (final MongoClient mongoSyncClient = MongoClients.create(MONGO_DB_CONTAINER.getReplicaSetUrl(DATABASE_NAME))) {
+            //2. But the database is not created yet, because we have not performed any writing operation.
+            assertFalse(
+                "Database: " + DATABASE_NAME + " is supposed to be here",
+                isDatabaseInMongoDB(mongoSyncClient, DATABASE_NAME)
+            );
+
+            //3. Perform an operation to create a new collection via mongoTemplate.
+            mongoTemplate.createCollection(Product.class);
+
+            //4. Now the database is created in MongoDB.
+            assertTrue(
+                "Database: " + DATABASE_NAME + " is supposed to be here",
+                isDatabaseInMongoDB(mongoSyncClient, DATABASE_NAME)
+            );
+        }
+    }
+
+    private boolean isDatabaseInMongoDB(
+        final MongoClient mongoSyncClient,
+        final String databaseName
+    ) {
+        Objects.requireNonNull(databaseName);
+        return StreamSupport.stream(
+            Spliterators.spliteratorUnknownSize(
+                mongoSyncClient.listDatabaseNames().iterator(),
+                Spliterator.ORDERED
+            ),
+            false
+        ).anyMatch(databaseName::equals);
+    }
+
+    static class Initializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
+        @Override
+        public void initialize(@NotNull ConfigurableApplicationContext configurableApplicationContext) {
+            TestPropertyValues.of(
+                String.format("spring.data.mongodb.uri: %s", MONGO_DB_CONTAINER.getReplicaSetUrl(DATABASE_NAME))
+            ).applyTo(configurableApplicationContext);
+        }
+    }
+
+    @SpringBootApplication
+    static class SpringBootApp {
+        public static void main(String[] args) {
+        }
+    }
+
+    @Data
+    @AllArgsConstructor
+    @NoArgsConstructor
+    @Setter(AccessLevel.NONE)
+    private static class Product {
+        private Long article;
+    }
+}