Think inside Container - Building Reliable infrastructure for Selenium Tests

I spoke and demonstrated “Think inside Container - Building Reliable and Scalable infrastructure for Selenium Tests” at Selenium Conference 2016 in London on 15 November 2016. The room was large and mixed, and the interest was in infrastructure that stays reliable once the suite leaves a laptop.

Purpose

Ship tests as containers, not as a folder of code that only runs on one laptop.

Testers own the reliability of their tests in the same way developers and the people running production own the software. That is usually difficult, slow, and dependent on a developer being free. Docker is one way to make the test environment something you can build, move, and throw away.

Need

Two trends were already visible in how software was being delivered:

• Docker was becoming the usual way to manage infrastructure with containers.
• Test code and the infrastructure under it were growing: more complexity, more dependencies, more languages, and a demand for reliability and speed at the same time.

Agenda

The session was about using containers for a growing test stack and for continuous delivery:

• What a container is, and how that applies to test automation.
• How Docker can shorten a run, make a clean environment cheap to set up, and shrink the gap between development, acceptance, and production.
• Examples that put a whole testing stack, Selenium included, in containers.
• Running the test container next to the application containers so a delivery pipeline stays manageable.
• Practices that keep a Docker setup from becoming another machine only one person can rebuild.

What you should leave with

• A working picture of Docker, and why a tester should care.
• Enough of a Dockerfile and Compose file to read a multi-container setup.
• A path for packaging an existing Selenium suite, or another runner, as a container you can move.
• A Selenium example you can take back to a project.
• A place to put those containers on a CI pipeline.

Demo and hands-on

The demonstration ran tests inside a container for web, with Selenium, and for mobile UI, with Appium on a real device.

• Slides: think-container
• teststack, the project opened for the demo
• Talk video

The original notes asked for feedback if the hands-on broke. The repository is still the place to look.

People

The other useful part of the two days was the corridor: attendees from other cities, old friends, and other speakers with a concrete idea rather than a product pitch.