At some point, however, developers started complaining that when they executed unit tests, their computer fans started roaring and the machine became painfully slow to use. We have been following setup procedures as described in the Spring Documentation for some time. The library itself handles downloading and caching MongoDB binaries suitable for your machine, and starting/stopping the server.

Under the hood, Spring Boot has logic detecting the presence of this library on classpath, and modifies MongoDB connections to point at an instance started by the library. …And voilà! Your tests connect to a database started just for the time of your tests being executed. In fact, Embedded Mongo is still recommended by theĪt a first glance it looks fantastic: you don’t need to modify your production code, you don’t even need to configure anything, just add a dependency: testRuntimeOnly('de.flapdoodle.embed:de.:2.2.0') Those articles still rank surprisingly high in search engines – things don’t just disappear from the Internet when they cease to be useful. Flapdoodle Embedded Mongo was immensely popular at some point and many tutorials were written about using it.

If you search the web for ’test spring boot mongo’ or similar terms, you will very likely end up with instructions which may harm your codebase. Finally, I will talk about how sar and other Linux tools can be used to measure the load on your machine. I will also guide you through the setup process of MongoDB using Testcontainers, and offer some tricks to improve Testcontainers performance. In this article I would like to share some of the problems connected with Flapdoodle Embedded Mongo and talk briefly about Spring tests to explain what causes those problems. This ultimately prompted us to migrate our code to a tool getting much hype recently – Testcontainers.

At some point, however, we realised that embedded Mongo was turning our builds into a nightmare. Until early 2020 there was not much choice and the default was to use ’embedded Mongo’ – my team was no exception. The following snippet shows how we can configure the embedded MongoDB instance manually.If your Spring application uses MongoDB, there is one question you will have to answer at some point: how to set up a database instance for your tests.

However, sometimes we might need to configure embedded Mongo database manually (e.g., when testing a specific DB version). Spring Boot will automatically start and configure the embedded database and then inject MongoTemplate instance for us.

Does spring start mongodb server