Open Source

Articles about Open Source by Sebastian Bergmann

An unbroken red wax seal on an envelope. A visual metaphor for untouched tests: as long as the seal is intact, the contents are provably undisturbed.

July 22, 2026

Untouched tests are half the proof

My favourite kind of bug fix only adds a new regression test and leaves every existing test untouched. I checked this claim against PHPUnit's own history: I learned the most from the counterexamples.

The image shows a colourful, chalky network of dots and connections on a black background. It is a playful visualisation of distributed, loosely coupled communities and thus fits perfectly as the mood for an article about the Fediverse.

January 18, 2026

Open Source, Open Feeds: Mastodon and PeerTube as online spaces for the PHP community

With phpc.social and phpc.tv, the PHP community is building its own donation-funded online spaces in the Fediverse – free from algorithms and fascist tech bros.

The image depicts a symbolic scene that represents cooperation and team spirit. The focus is on several hands arranged in a circle from above, working together to bring wooden puzzle pieces together. The hands belong to different people wearing different clothes. Some light-coloured shirts and grey sleeves are visible. The scene takes place on a green meadow, conveying a sense of naturalness and openness. The light-coloured puzzle pieces represent the individual components that must be put together to form a larger whole.

January 7, 2026

How PHP and its ecosystem test each other

PHP tests Laravel, Symfony, PHPUnit, and more every night. PHPUnit tests PHP. This is Open Source collaboration at work.

The image shows a row of electrical circuit breakers with wooden letter blocks placed on top of each breaker. The blocks spell out the phrase "BLACKOUT." In front of the circuit breakers, there is a lit candle, symbolizing the situation of a power outage or blackout where electric power is unavailable and people rely on candles for light. The setting appears to be indoors, and the candle's flame provides a warm light illuminating the breakers and the surrounding area. The image visually represents the concept of losing electrical power with the word "blackout" and the candlelight.

November 11, 2025

Open Source Blackout

Are you prepared for a world in which your projects freeze, deployments stall, and tech giants can no longer rely on free community-run infrastructure?

The image shows a wooden staircase leading through dunes to the beach, running towards a sunrise or sunset. The years from 2026 to 2035 are painted large and white on the individual steps, as if symbolising the path to the future. At the end of the staircase, where the light is strongest, the journey seems to lead into the coming years, while the wide sky and calm sea in the background convey a peaceful, expansive mood.

October 22, 2025

A look ahead to 2035

I discuss key issues for the future relating to ethics, digital sovereignty, Open Source, and web standards.

A person wearing a backpack stands on a rocky ledge overlooking a range of green mountains under a partly cloudy blue sky.

June 8, 2025

30 Years of PHP, 25 Years of PHPUnit

I look back on 30 years of open source innovations.

The image shows a panoramic view of a harbour with a train on an elevated railway bridge in the foreground. On the left is a modern building with a striking glass façade, which is the Elbphilharmonie concert hall in Hamburg. In the background, several ships and cranes can be seen, indicating port activity. The weather is cloudy but bright, suggesting late afternoon or early evening. The scene appears both calm and industrial.

March 11, 2024

PHPUnit Code Sprint: March 2024

I recollect my experience at the PHPUnit project's most recent code sprint.

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