Software Development, Testing & Open Source

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July 1, 2026

Precision and Clarity: What is new in PHPUnit 13.2?

Selecting exactly the tests you want, finer control over the order they run in, faster and clearer output when they fail, and more expressive test doubles: I walk you through what is new in PHPUnit 13.2.

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June 24, 2026

Merging code coverage data

Merging code coverage data from parallel CI jobs has long been fragile and error-prone. These problems are finally solved.

A glowing cockpit instrument panel in deep blue light, its dials, throttle levers, and backlit gauges tracing speed and status: a metaphor for reading the telemetry your test suite records on every run.

June 17, 2026

What your test run already knows

On every run, PHPUnit knows how long each test took, how much memory it used, and why it failed. Most of that evaporates. otr-report reads it back out of the Open Test Reporting logfile and puts it within reach.

A mechanical stopwatch lies on a weathered wooden surface, waiting to be started. It symbolises how the duration of a test run has become a measurable factor that determines more than just developer convenience.

June 12, 2026

Speed as a security feature

How fast is your test suite, and what vulnerabilities does an LLM agent therefore fail to detect? What was long considered a productivity issue is now part of the security debate.

An astronaut in a detailed white spacesuit rides a small cyan-glowing rocket through deep, star-speckled space, leaning forward as a brilliant orange flame and a billowing trail of glowing exhaust streak out behind, with a single bright star shining in the upper right: a metaphor for taking a sluggish test suite and propelling it to blazing speed.

June 11, 2026

Turbo-Charging Your PHPUnit Suite

Slow tests destroy flow, kill TDD, and erode trust until nobody runs the suite. The fix has four tiers, and the biggest wins come from test design, not from infrastructure or parallelisation.

A young man in jeans and a white long-sleeved shirt, rendered in black and white, swings a large green shield emblazoned with a bright red checkmark, batting away a flurry of crumpled paper balls against a soft peach background – a metaphor for using tests as an active defence that knocks out security weaknesses before they can reach production.

June 10, 2026

Test-Driven Security

For every vulnerability we find in production, there is a test that, had it existed, would have prevented it. Test-Driven Security treats the CWE list as a checklist and PHPUnit as the tool we already have in our workflow.

The illustration shows a programmer in a dark office in front of a laptop. Like an investigator, he searches for clues on a pinboard full of photos, notes and red threads – an emotional introduction that picks up on the familiar feeling of bug hunting. The accompanying text explains how to design software so that debugging does not have to feel like criminal investigation work.

June 3, 2026

Debugging as a design goal

Why do some bugs feel like a short detective story, while others feel like a never-ending thriller? I show you which decisions make your software debuggable.

A simple wooden bridge crosses a flowing stream in a straight line, leading into a green forest. A symbol of the fact that the simplest solution is often the most effective.

May 27, 2026

Code I do not have does not cause any problems

Not every problem requires new code. And every line we do not write is a line that will not cause any problems.

Only what must exist has a door. The safest door is the one that was never built.

May 20, 2026

The attack surface begins in the repository

We protect what exists. But do we ask often enough whether it should exist at all? How removing unused branches can protect against Poisoned Pipeline Execution.

A heavy steel chain breaks at its central link in a burst of red-orange sparks, with fragments of binary digits scattering outward against a deep blue, circuit-lit background. A visual metaphor for the supply-chain security failure that workflow hardening is meant to prevent.

May 17, 2026

Hardening GitHub Actions workflows

A walk through the GitHub Actions weaknesses in PHPUnit's workflows, how each one could have been exploited, and what was changed to close them.

May 13, 2026

ComoCamp 2026

Three days in Vienna, three days of ComoCamp: my report on inspiring workshops, exciting open space sessions, and the uniquely open, collaborative atmosphere.

A telescope on a tripod stands silhouetted against a clear starry sky. A symbol of how the right tools sharpen our view of what matters.

May 6, 2026

Closures, Clarity, and Control: What is New in PHPUnit 13.1?

Closures as data providers, richer Open Test Reporting, custom issue trigger resolvers, and significant changes to code coverage: I walk you through the changes.

The image shows five wooden blocks with symbols representing interpersonal skills. A hand deliberately highlights the cube with the red heart and the inscription "EMPATHY". The warm, calm atmosphere emphasises empathy as a technical skill in software development.

April 29, 2026

Technical debt is not malice

Technical debt is not malice, it is context. An argument for why empathy is a technical skill that matters more than you think.

A glowing magnifying glass over a bug symbol, held by a hand, against a dark background of binary code and geometric patterns. A visual metaphor for the disciplined investigation of performance problems.

April 23, 2026

Debugging Performance in PHP

"It feels slow" is not a diagnosis. I explain the three disciplines that turn vague complaints into actionable data: tracing, profiling, and benchmarking.

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April 18, 2026

The Bouncer in the Dependency Resolver

Composer 2.9 moved security advisory enforcement from an opt-in third-party package into the resolver itself. This article walks through how the mechanism works, how it relates to the older packages it replaces, and where it can bite you.

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April 15, 2026

Everything we have

In a world with endless possibilities for code to be wrong, one approach alone is not enough to make our software truly robust.

The image shows an abstract, futuristic design with a dominant, glowing question mark as its central motif. It emerges from a chaotic, undulating landscape of geometric pixels and voxel-like structures in intense shades of pink, purple and blue. These create depth and dynamism. The chaotic background resembles a seething, digital terrain that symbolises disorder and complexity. The question mark rises stably and questioningly from it – perfect as a visual mood for fuzz testing, where random chaos reveals security.

April 8, 2026

Security through chaos

This practical deep dive into the philosophy behind "security through chaos" shows that security does not come from perfect foresight, but from surviving chaos.

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April 1, 2026

Beyond Best Practices

Testing, code reviews and documentation are all essential prerequisites that constrain the autonomy of AI, thereby safeguarding human agency in software development.

The image depicts a modern software development workspace, with two developers collaborating at a shared desk. In the foreground, a woman wearing glasses and a warm, cognac-coloured jumper is typing on a keyboard and engaging with the team. Behind her, a male developer in a light green shirt is also focused on his work.

March 25, 2026

Effective Code Reviews

Pair, pull, or post-push? Find the code review strategy that is right for your team.

A road disappearing into thick fog. A symbol of how AI-generated code may look readable and plausible to us, but we cannot tell whether it will lead us to the right destination.

March 18, 2026

Faster than understanding

An AI coding agent implemented a complex software metric in 15 minutes. I have now spent hours trying to figure out whether the implementation is correct. Is this really a productivity boost?

Glass sphere resting on wet pebbles at the shoreline, reflecting a pier and sunset, symbolizing a shift in perspective and bringing clarity to complex testing practices.

March 11, 2026

From anti-pattern to clarity

The any() matcher is deprecated. But migration is easier than you think – and leads to better tests.

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March 4, 2026

Better than withConsecutive()

I explain how PHPUnit 13's parameter set matchers finally solve the problem that made upgrading to PHPUnit 10 such a challenge.

The image shows a close-up of printed financial data on paper, with multiple vertical columns of numbers in black, green, and red ink representing values such as prices or changes. A metallic pen lies diagonally across the sheet, suggesting analysis or review of the numerical information.

February 25, 2026

Replay Testing

Replay Testing leverages the memory of your event sourcing system to test new versions with real history and shows which oracles truly inspire confidence in your changes.

The image illustrates that valuable insights can be gained from recorded events through skilful processing and analysis, a metaphor for the value of event sourcing and automated testing in software development.

February 20, 2026

From Events to Insights

Event Storming, DDD, CQRS, and Event Sourcing are intertwined: the tests not only check the events, but also become living documentation and a bridge between technical expertise and code.

February 11, 2026

How my understanding of software changed

A classic database only stores the "now" and forgets history. In this article, I describe my journey to DDD and event sourcing and explain why we need to learn to model time itself.

February 4, 2026

Data Provider or Properties?

One test, hundreds of inputs, and an automatic edge case search. But property-based testing has a hidden pitfall that many overlook.

The image shows a hand against a dark background, presenting a glowing light form that is drawn half like a brain, half like a light bulb. The scene conveys focused clarity and symbolises small inputs with great insight – fitting for shrinking in property-based testing.

January 28, 2026

Smaller input, greater insight

Shrinking is the unsung hero of property-based testing. I show you how it helps to make inevitable errors understandable.

January 21, 2026

Property-Based Testing

We only test what we think of. That is precisely what can become a problem.

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.

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January 14, 2026

Type-Safe Collections

Does PHP really need generics? A controversial thesis with a practical solution.

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.

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December 31, 2025

The Stub/Mock Intervention

Self-sabotaging mock objects? With PHPUnit 12.5, that's a thing of the past because the test runner now asks the right question: Do you really need a mock object, or would a test stub suffice?

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December 24, 2025

A festive break

I take a break from my weekly articles and invite you to a free online event where I will present the latest improvements to PHPUnit.

The image shows an aircraft flight recorder, commonly known as a "black box", resting on the seabed under water. The cylindrical orange device is slightly rusted and mounted on a base plate, with a rectangular attached unit behind it. A large white label on the cylinder reads "FLIGHT RECORDER DO NOT OPEN".

December 17, 2025

A flight recorder for your code

Your PHP project has no tests and an upgrade is pending? The classic dilemma: to introduce tests, you have to change code – to change code, you need tests. How can you break this cycle? With characterisation tests.

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December 10, 2025

Seeing the Truth: Test Oracles

Your tests are successful. But are they really? Without a suitable test oracle, you will never know.

This image illustrates the contrast between technical motivation, represented by flowing, dynamic data streams, and domain motivation, represented by solid, stable foundational concepts. This visual metaphor illustrates the main point that DTOs facilitate the movement of data between layers, while value objects represent unchangeable domain concepts that form the basis of business logic. The layered architecture also illustrates how these objects are used in different contexts: technical boundaries versus core business logic. It emphasises the stability and predictability that immutability brings to testing practices.

December 3, 2025

Testing with DTOs and Value Objects

Know the differences between data transfer objects and value objects and understand why immutability helps with testing.

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November 28, 2025

Testing with(out) dependencies

Why distinguishing between test stubs and mock objects in PHPUnit significantly improves the quality and readability of tests.

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November 19, 2025

Path Coverage or Mutation Testing?

How thoroughly do your tests cover the code, and how reliably do they detect real errors? I show you how to find out.

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?

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November 5, 2025

More control, less friction: What's new in PHPUnit 12.4?

Discover how PHPUnit 12.4 helps you get there with less friction and more insight.

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October 29, 2025

Modern PHP Development

Modern PHP development combines proven principles with the latest tools. It brings together documentation, quality, automation, and AI.

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.

The picture shows a light bulb lying on a wooden surface. The light bulb is lit and creates a warm atmosphere. Right next to the light bulb is a small pile of various old metal keys. The interplay between the glowing light bulb and the keys symbolically conveys the idea that ideas (light bulb) can be the key (bunch of keys) to new possibilities or solutions.

October 15, 2025

PHPUnit features that surprise even professionals

Discover the hidden capabilities of PHPUnit and learn how to get the most out of your tests with clever features.

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October 7, 2025

From AmigaBASIC to AI

A personal journey from my first lines of BASIC on the Amiga to the question of how AI will shape the next generation of developers.

The image shows several people working together to assemble a puzzle made up of yellow pieces that form the shape of a light bulb. The light bulb typically symbolises an idea or innovation. The scene takes place on a wooden table, which also holds a cup of coffee, a glass of water, an open laptop and some documents. The people's hands are visible as they fit the puzzle pieces together, illustrating collaboration and teamwork.

September 1, 2025

Innovation through collaboration: The highlights of PHPUnit 12.3

Discover how collaboration with real-world developers has shaped the latest advancements in PHPUnit 12.3.

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June 16, 2025

Psalm or PHPStan?

Psalm or PHPStan: which tool is the better choice for code analysis? Or is it worth combining both tools for maximum code quality?

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June 8, 2025

30 Years of PHP, 25 Years of PHPUnit

I look back on 30 years of open source innovations.

Collaborative prioritisation of quality goals with LASR

May 10, 2025

ComoCamp 2025

I am thrilled by the inspiring workshops, exciting open space sessions and the uniquely open, collaborative atmosphere of ComoCamp.

August 25, 2024

SoCraTes 2024

SoCraTes has enriched and motivated me in a lasting way through inspiring discussions, exciting sessions on topics such as PHP, software testing, security and open-source funding, as well as the special, collaborative atmosphere.

Tool wall on which a variety of hand tools are neatly arranged

June 25, 2024

PHP_CodeSniffer or PHP-CS-Fixer?

Should PHP_CodeSniffer or PHP-CS-Fixer be used to get code "in shape"? Should both tools even be used together?

A man is sitting on a dune covered with dry grass. He appears pensive or perhaps even sad, as he rests his head on his arm with one hand while looking down.

March 22, 2024

PCOV or Xdebug?

Should you use PCOV or Xdebug to collect code coverage data? I give a personal answer.

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.

The image shows a yellow diamond-shaped traffic sign with the black inscription "DEAD END". It is located in an urban environment, in front of a building with large windows and metal bars. In the background, there are other buildings with typical metal external staircases, as are often found in some neighbourhoods. The sign indicates that the road ends at this point and that it is not possible to drive through.

November 28, 2022

PHP 7: Security Support Ends. Now what?

Security support for PHP 7 has ended. What does this mean for you?

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April 4, 2022

How I manage test fixture

I reflect on why I no longer write setUp() methods.

The image shows two people starting on a running track. In the foreground, a person in a red sports outfit is seen in the starting position for a sprint, ready to run. In the background, another person is also in the starting position. The image conveys a sporty and competitive moment on an outdoor athletics track in daylight, surrounded by trees and buildings.

August 2, 2021

Ready Or Not, Here It Comes

Is your software ready for PHP 8.1? Now is the time to find out.

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April 21, 2021

Do not mock what you do not own

If you use abstractions you don't own, testing may be difficult.

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October 8, 2020

Caching makes everything faster. Right?

While working on PHPUnit, I encountered an interesting problem.

The image shows two chess pieces on a light, almost white background. The central piece, a black king, stands upright. Next to it lies another king – presumably white – on its side, apparently defeated. The scene appears minimalistic and focuses exclusively on this symbolic moment, which is often interpreted as representing victory and defeat.

July 6, 2020

Failing IT Projects

I explain how we can learn from failed IT projects.

The image shows an analogue wall clock with a yellow frame hanging on a white wall. The time is approximately 6:50 p.m. The clock face has a simple design and the background of the clock and the wall are white, giving the image a very minimalist look. There is a lot of empty space on the left, while the clock is located on the right side of the image.

June 5, 2020

Who wound the clock?

I explain why PHPUnit no longer looks at the clock.

The image shows a wooden sign with the word "CLOSED" written on it. The sign is photographed at an angle and, thanks to its warm, brownish colouring, blurriness and strong grain, has a particularly atmospheric and nostalgic feel. It is reminiscent of a photograph taken in a small, cosy shop or café at closing time.

February 21, 2020

PHPUnit: A Security Risk?

The long story of a security problem that should not have been one.

The image depicts a tranquil seascape at sunset or sunrise. The water's surface reflects the warm colours of the sky, which glows in shades of orange, yellow, blue and violet. Several birds can be seen flying in the sky, creating a peaceful and relaxed atmosphere. The silhouettes of the birds stand out clearly against the colourful horizon, emphasising the vastness and tranquillity of the scene. In the background, a dark headland or coastline can be seen, completing the picture.

February 7, 2020

Migrating to PHPUnit 9

In the tension between backward compatibility and progress, a good developer experience must not be neglected.

The image shows a concrete wall with a rough surface and visible horizontal lines and joints. Shadows fall on it, forming patterns, presumably from plants or leaves. The shadows create an interesting interplay of light and dark, giving the image a calm, natural atmosphere.

February 1, 2019

Blast from the Past

Package managers are worthwhile targets, even if no one uses them anymore. Background information on the breach of the PEAR infrastructure of the PHP project.