Polishing.

Move Testcontainer creation into utility.

See #632

mongodb/util/src/main/java/example/springdata/mongodb/util/MongoContainers.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example.springdata.mongodb.util;
+
+import org.testcontainers.containers.MongoDBContainer;
+import org.testcontainers.utility.DockerImageName;
+
+/**
+ * Utility methods to create a {@link MongoDBContainer}.
+ *
+ * @author Mark Paluch
+ */
+public class MongoContainers {
+
+	private static final String IMAGE_NAME = "mongo:5.0";
+	private static final String IMAGE_NAME_PROPERTY = "mongo.default.image.name";
+
+	public static MongoDBContainer getDefaultContainer() {
+		return new MongoDBContainer(DockerImageName.parse(System.getProperty(IMAGE_NAME_PROPERTY, IMAGE_NAME)))
+				.withReuse(true);
+	}
+}