How Gappless Setup Automated Testing of Its SaaS Application

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About the case

Built on the Mendix platform, Gappless is a SaaS application for managing jobsite registrations at construction projects. Because the development team is constantly adding new features, testers previously had to manually test the same flow over and over. Now, with Mendix Application Test Suite (ATS) from Mansystems, Gappless can automatically test the core without any manual intervention, which saves time and frees up the test team to focus on new features.


Built on the Mendix platform, the Gappless SaaS solution manages the core process of a construction project. Job-site managers and supervisors must meticulously document the quality of their projects right at the job-site, in so-called registrations. Faulty registrations can hamper agility and profitability for construction companies.

Even a smaller company might produce several thousand registrations annually, which means Gappless can save companies tens or hundreds of thousands of euros each year. Already Gappless has been used in more than 150,000 registrations for projects valued at more than €100 million.

When building the initial application, testing the core functionality was essential to ensure easy adoption by launching customers. Gappless worked with a dedicated test team to ensure the quality of the app. At the time, the development was outsourced; therefore, it was crucial for Gappless to test their own app for acceptance. The manual testers did not have a technical background, but understood their customers and their usage of the application.

On the acceptance environment, the manual test team would test all core functionalities. With every new feature, the testers ran through the same test script to ensure an error-free production environment.

“We spent every day of the week testing the core functionality, because our development team was constantly adding new features,” said Joshah Fraanje, lead tester at Gappless. “It was quite cumbersome to test the same flow in the application over and over again. We knew there had to be a better way.”

"Mendix ATS helps our test team to focus on new and changed features while keeping an eye on the rest of the application to detect undesired side effects."

Paul Poetsma
Lead Architect, Gappless


A year after the launch of the SaaS solution, the test team began to evaluate automated test tooling. It was obvious that automation would reduce time spent on manual testing and test coverage could be expanded. In addition, Gappless would have more continuous control over the quality of their application.

Gappless evaluated many test tools and decided on a well-established tool for automated testing. Unfortunately, custom widgets in the application prevented them from using the tool as it was intended. “I had to turn into a C# developer to make the tool work for us,” noted Fraanje. “Very quickly, we were forced to resort back to testing our application manually.”

As soon as Mendix Application Test Suite (ATS) entered the market, Gappless was one of the first customers to adopt the product. Actions were built for the custom widgets, and Gappless could make and run test scripts without any development know-how. In 2016, the Recorder feature in ATS was introduced, allowing the test team to make test scripts even easier and quicker.

When starting with ATS, Gappless needed to create test scripts and test suites. Fraanje took time to set up a clean test structure, always keeping every test script as short as possible. Although this takes a bit more time to keep your test scripts up-to-date, the usage is clean and always runs smoothly.

The test team involved the development team in creating the initial test scripts. “We helped to create many test scripts to be able to test the ‘Happy flow’ within the application and automate testing for the core of the application,” said Paul Poetsma, lead architect at Gappless. “This way, we were fast and it helped the adoption of testing within the development department.”


Gappless tests the entire core application with ATS. While the test team was previously busy going through test scripts every day, they are now able to work on ATS just one day a week. They build test scripts and look at the scheduled test scripts every day to follow up. Their work has changed dramatically. In the last four releases, Gappless was able to automatically test the core without any manual intervention.

The company is now in the process of starting to test other modules and the ‘unhappy flow’. Gappless is in the constant process of optimizing their application and customer experience. Their roadmap includes integrations with other systems, such as the GIS application, as well as improving forms and reporting.

“Mendix ATS helps our test team to focus on new and changed features while keeping an eye on the rest of the application to detect undesired side effects”, summarized Poetsma.

About Gappless

Gappless provides complementary mobile and SaaS applications for project-based manufacturing and services industries. Customers include some of the largest construction companies in the world.