Presented by Quinten Krijeger and Ernst Naezer, Engineers at ING Netherlands At ING we build financial scenario planning software. Using Docker and Docker Compose we develop, test and host our application consisting of multiple containers. This talk focuses on how we test our software stack. We use Docker Compose to inject components that stub services or simulate infrastructure failures. We developed and open sourced a Gradle plugin to take care of the heavy lifting, allowing us to test the images using either unit tests defined in code or by a dedicated test image. The shown techniques fully support the agile process, by giving instant feedback on the features under simultaneous development against the entire application stack. We are now confident when merging a feature to master.