VOOZH about

URL: https://thenewstack.io/how-testcontainers-is-demonstrating-value-as-a-key-ci-tool/

⇱ How Testcontainers Is Demonstrating Value as a Key CI Tool - The New Stack


TNS
SUBSCRIBE
Join our community of software engineering leaders and aspirational developers. Always stay in-the-know by getting the most important news and exclusive content delivered fresh to your inbox to learn more about at-scale software development.
REQUIRED
It seems that you've previously unsubscribed from our newsletter in the past. Click the button below to open the re-subscribe form in a new tab. When you're done, simply close that tab and continue with this form to complete your subscription.
The New Stack does not sell your information or share it with unaffiliated third parties. By continuing, you agree to our Terms of Use and Privacy Policy.
Welcome and thank you for joining The New Stack community!
Please answer a few simple questions to help us deliver the news and resources you are interested in.
REQUIRED
REQUIRED
REQUIRED
REQUIRED
REQUIRED
Great to meet you!
Tell us a bit about your job so we can cover the topics you find most relevant.
REQUIRED
REQUIRED
REQUIRED
REQUIRED
REQUIRED
Welcome!

We’re so glad you’re here. You can expect all the best TNS content to arrive Monday through Friday to keep you on top of the news and at the top of your game.

What’s next?

Check your inbox for a confirmation email where you can adjust your preferences and even join additional groups.

Follow TNS on your favorite social media networks.

Become a TNS follower on LinkedIn.

Check out the latest featured and trending stories while you wait for your first TNS newsletter.

PREV
1 of 2
NEXT
VOXPOP
As a JavaScript developer, what non-React tools do you use most often?
Angular
0%
Astro
0%
Svelte
0%
Vue.js
0%
Other
0%
I only use React
0%
I don't use JavaScript
0%
Thanks for your opinion! Subscribe below to get the final results, published exclusively in our TNS Update newsletter:
NEW! Try Stackie AI
From clobbered drafts to real-time sync
Apr 14th 2026 10:00am, by David Moore
TypeScript 6.0 RC arrives as a bridge to a faster future
Mar 14th 2026 9:00am, by Darryl K. Taft
Mastra empowers web devs to build AI agents in TypeScript
Jan 28th 2026 11:00am, by Loraine Lawson
2023-04-10 07:55:08
How Testcontainers Is Demonstrating Value as a Key CI Tool
CI/CD / Containers / DevOps

How Testcontainers Is Demonstrating Value as a Key CI Tool

Testcontainers is a library originally written in Java that helps developers run module-specific Docker containers while the app is being built in order to simplify integration testing.
Apr 10th, 2023 7:55am by Chris J. Preimesberger
👁 Featued image for: How Testcontainers Is Demonstrating Value as a Key CI Tool

When software developers are building their microservices for use inside Docker containers, it saves a great deal of time and effort for them to also test for various dependencies in parallel instead of starting from scratch after the app is done. As those dependency dots are connected, they often require changes to the app, which means doubling back and re-doing the code. And nobody likes re-doing anything.

This is where something new called Testcontainers comes to the proverbial rescue. Testcontainers is a library originally written in Java that helps developers run module-specific Docker containers while the app is being built in order to simplify integration testing. These Docker containers are lightweight, and once the tests are finished, the containers are destroyed, and developers can move on to the next project.

Modules Program

Software company AtomicJar, a pioneer in this sector, on April 5 launched its Testcontainers Official Modules program with the backing of several major vendors. Redpanda, StreamNative, Neo4j, Cockroach Labs, LocalStack, Oracle and Yugabyte were among the first to declare support for Testcontainers.

The modules catalog features more than 50 modules supporting a list of often-used technologies and provides certification, support, and maintenance of Testcontainers modules for the development community. Each community partner is committed to supporting the program as the preferred way of testing their work and to developing with other partners locally.

“Testcontainers allow developers to test and develop their code against the real dependencies they will use when the app goes live for use,” Eli Aleyner, co-founder of AtomicJar, told The New Stack. “For example, a developer could write a test that is to be executed with a real instance of Kafka, MySQL or any other technology. When the test is complete, it will tear down any dependencies. This allows developers to create self-contained, repeatable and idempotent tests that can be run either locally or in the continuous integration process (CI).”

In the background, Testcontainers utilizes its own containers to spin up the dependencies, Aleyner said. “So when a developer uses Testcontainers to say: ‘I want an instance of Kafka,’ before the test runs, the Testcontainers library will fetch the Kafka container, start it locally, handle all the port mapping and other details automatically.”

The larger impact of this approach is that it enables organizations to give developers more control and allow them to get more confidence in the software they write before checking in their code, Aleyner said.

“Previously, the only place developers used to discover integration issues was during the CI process. With Testcontainers, developers are able to shift this to the left, find issues faster and iterate quicker,” Aleyner said.

There is no substitute for speed in agile software development, and tools like this one help developers stomp down on the accelerator.

Started in Java

The Testcontainers project started in 2015 in Java and has grown to include hundreds of thousands of instances of Postgres, Elastic, MySQL, and other enterprise components, Aleyner said. Testcontainers has since evolved beyond the Java ecosystem libraries into .Net, Go, Node.js, Python, Rust and Haskell as those communities begin to realize the value of quicker iteration enabled through this library.

Since its inception, Testcontainers library has been implemented in seven languages, and it has also been embraced by the development community from large to small companies, Aleyner said. DoorDash, Uber, Spotify, Netflix, Capital One, and several others have talked publicly about using Testcontainers to simplify their Testing setup, he said.

“In aggregate, we are currently tracking around 6 million Docker image pulls for Testcontainers a month,” Aleyner said. “We have seen the Testcontainers library being downloaded 100 million times in January of this year; we crossed 50 million downloads in May of last year, so the technology is getting a lot of traction.”

TRENDING STORIES
Chris J. Preimesberger, a contributing writer/editor at several publications since June 2021, is former editor in chief of eWEEK. He was responsible for the publication's coverage for a decade (2011-2021). In his 16 years and more than 5,000 articles at...
Read more from Chris J. Preimesberger
SHARE THIS STORY
TRENDING STORIES
TNS owner Insight Partners is an investor in: AtomicJar, Docker.
SHARE THIS STORY
TRENDING STORIES
TNS DAILY NEWSLETTER Receive a free roundup of the most recent TNS articles in your inbox each day.
The New Stack does not sell your information or share it with unaffiliated third parties. By continuing, you agree to our Terms of Use and Privacy Policy.