Tested with Squish

European XFEL

Learn how Squish keeps complex control system reliable and error-free, enabling scientists to run million-dollar experiments without a second lost

Powering Global Scientific Discovery

European XFEL (European X-Ray Free-Electron Laser Facility) is a multi-national non-profit research institute which provides unique research opportunities for scientists globally through the design, construction, operation and development of a linear accelerator based Free-Electron Laser source.

Boasting the world’s largest X-ray laser, European XFEL (EuXFEL) enables applied scientific research in diverse disciplines by supporting researchers to explore fundamental aspects of matter and energy — anything from the development of new medicines and therapies to novel solutions for energy storage to elucidating complex intra-planetary processes.

This type of breakthrough scientific exploration is possible thanks to the X-ray laser’s extremely high peak brilliance, high repetition rate (27,000 flashes per second) and extremely short pulse duration (less than 100 quadrillionth of a second), allowing for advancements in research areas previously inaccessible through conventional scientific methods.

But with experiments happening in ultra-short pulses the stakes are impossibly high. Software failure isn’t just an inconvenience, it’s a lost opportunity for science.

It’s really critical for us to execute GUI tests for all available platforms, always.

Anna Klimovskaia, Software Test Manager at EuXFEL

Meeting the Must-Have Criteria for GUI Test Automation

When evaluating GUI testing tools, the EuXFEL team focused on a set of essential criteria:

First, the tool needed to support command-line test execution to fit seamlessly into their CI/CD workflows.
Second, it had to allow user-defined libraries, which are vital for building reusable, modular test logic tailored to their custom-built Karabo system.
Finally, cross-platform support was non-negotiable, as Karabo runs on various Linux distributions and Windows systems.

After assessing several options, Squish was the solution that met these technical and operational requirements, making it the clear choice.

Karabo Framework Scene

How Squish Helped Build Confidence Into Every Click

To ensure a flawless experience for visiting scientists, who may only have a five-day window for life-changing research, EuXFEL relies on Karabo, its in-house SCADA system that controls everything from magnets and motors to pumps and undulators in the laser’s vast experimental tunnels.

But Karabo’s GUI presents a major challenge when scientists are using it for the first time, under extreme time pressure, to run experiments with little margin for error.

So, manual testing simply isn't scalable.

"The GUI provides an intuitive human interface to complex hardware setups," says Anna Klimovskaia, Software Test Manager at EuXFEL.
"We don’t have the resources to test it manually,"

So Anna’s team turned to Squish GUI Tester to build trust not just in their software, but in the outcomes their users rely on.

About Karabo

The Karabo framework, an in-house developed system used for supervisory control and data acquisition (SCADA), serves as the software behind EuXFEL’s hardware operation. The Karabo GUI is built using a client/server architecture written in Python with both standard Qt- and custom-UI controls, and its primary function is to operate equipment in EuXFEL’s experimental hutches, including magnets and undulators, moving motors, initiating pumping, and other hardware operations in its long tunnels. Scientists visiting the institute schedule, typically, five-day experiments in the hutches, and interact with the Karabo GUI to accomplish their research. With time being the limiting constraint, it is vital that Karabo remains functional and defect-free.

Other terms

SCADA (Supervisory Control and Data Acquisition): Industrial software for managing large-scale hardware systems — think of it as the digital brain behind lasers, magnets, and sensors.

GUI (Graphical User Interface): The user-facing interface that allows researchers to interact with Karabo using visual elements instead of code or terminal commands.

Robot Framework: A test automation framework that uses simple syntax to write scalable test cases — perfect for integrating with Squish.

Property Verification: Squish’s method of comparing specific properties of UI elements to spot even subtle regressions or inconsistencies.

Accelerating Quality Without Compromising Experiment Time

Squish is now deeply embedded into EuXFEL’s testing pipeline, enabling automated verification of Karabo’s graphical user interface.

Here’s how the QA team made it work:

Tests are triggered through command-line integration, ideal for continuous workflows
Reusable libraries allow modular and scalable test development
Built-in cross-platform support ensures consistency across Linux distributions and Windows
Robot Framework drives Squish through keyword-based test cases for greater maintainability
Snapshot comparisons detect even minor GUI differences across platforms using property verification

EuXFEL even built a custom test result database to collect, store, and visualize nightly test runs, empowering developers to monitor quality trends and respond rapidly to regressions.

Results

This is how QA Team Made it Work with Squish

Squish is now deeply embedded into EuXFEL’s testing pipeline, enabling automated verification of Karabo’s graphical user interface.

Increased GUI test coverage across multiple operating systems

Reduced risk of downtime during critical scientific experiments

Enhanced test reliability through cross-platform regression checks

Enabled fast feedback loops via integration with CI and test reporting systems

Boosted developer confidence and code quality with nightly testing

Explore Squish GUI Tester Interactive Product Tour

Protecting Beam Time and Research Progress

Every second of beam time is expensive and precious not just in monetary value, but in the research breakthroughs it can enable. Downtime due to a buggy interface? Unacceptable.

By automating GUI testing, the EuXFEL QA team has minimized the risk of last-minute failures, ensured consistent software behavior across all systems, and freed up time for engineers to focus on core development.

Beam time is extremely precious in terms of capital cost, but also to our scientific users… we cannot afford to lose time.

That focus on reliability translates directly into better research outcomes, and higher trust in the platform.

Squish as a Strategic Partner in Scientific Innovation

Looking forward, Ms. Klimovskaia aims to increase GUI test coverage as Karabo evolves and expands. This includes:

Covering more Karabo scenes with GUI tests
Running tests on more platforms as Karabo is deployed on new systems
Further aligning GUI and unit test development
Continuing to benefit from Squish’s strong technical support

Ms. Klimovskaia emphasized the excellent support received from Squish engineers solving implementation issues.

About European XFEL

European XFEL (European X-Ray Free-Electron Laser Facility) is a multi-national, non-profit research institute operating the world’s largest X-ray laser. Through its high-tech infrastructure, EuXFEL offers global scientists unprecedented research opportunities across disciplines: from life sciences and materials research to planetary physics and energy storage solutions.

With its X-ray laser producing 27,000 flashes per second and pulse durations shorter than 100 quadrillionths of a second, EuXFEL enables breakthrough research in previously inaccessible areas, thanks to extreme brilliance, ultra-short pulse length, and high repetition rate.

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