You’re sitting in a stall at Google’s Mountain View headquarters back in 2006. You’ve got business to attend to. But as you look up at the back of the door, you aren’t staring at a blank wall or some graffiti about a manager. Instead, there is a flyer. It’s titled Testing on the Toilet. It has code snippets. It has a "Total Test Time" estimate. It basically demands that you learn about dependency injection while you pee.
This sounds like a joke. It isn't.
The "Testing on the Toilet" (TotT) program is one of the most famous examples of "culture hacking" in the history of software engineering. It wasn't born out of a corporate mandate from the C-suite to increase productivity metrics by 4.2%. It was a grassroots movement by a group called the Google Testing Grouplet. They were tired of bad code. They were tired of broken builds. They realized that if you want to change how thousands of distracted, brilliant, stubborn engineers work, you have to catch them when they literally have nothing else to do.
The Weird Origins of the Grouplet
Software testing used to be an afterthought. Honestly, in many companies, it still is. You write the feature, you ship it, and you pray the QA team finds the bugs before the customers do. In the mid-2000s, Google was growing so fast that their codebase was becoming a tangled mess. Build times were exploding. Tests were "flaky"—meaning they passed sometimes and failed others for no clear reason.
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The Testing Grouplet was a band of volunteers. They didn't have formal authority to tell anyone how to write code. So, they got creative. They realized that engineers at Google were constantly flooded with emails, chat messages, and meetings. The only place where an engineer was guaranteed to be offline? The restroom.
They started printing out these one-page flyers and taping them to the inside of stall doors across the entire campus. Every week. They’d physically walk from building to building, replacing the old flyers with new ones. It was low-tech. It was weird. It worked.
Why the Bathroom Strategy Actually Ranks as Genius
Most corporate training is a slog. You sit in a windowless room for four hours while a slide deck kills your soul. Testing on the Toilet flipped the script.
The flyers were designed to be read in under two minutes. They focused on a single, actionable concept. Maybe it was how to use a "Mock" object, or perhaps it was a reminder of why global state is the enemy of testable code. By breaking down complex computer science topics into "bathroom-sized" chunks, the Grouplet lowered the barrier to entry.
You’ve probably heard of the "curse of knowledge." It’s when experts forget what it’s like to be a beginner. The TotT authors fought this by using a conversational, almost cheeky tone. They knew their audience. They knew a Google engineer would instinctively want to solve the little "puzzle" included at the bottom of the page. It turned a mundane biological necessity into a brief, high-intensity learning window.
The Friction of Changing Developer Culture
It wasn't all sunshine and successful deployments. Some people hated it. There were stories of engineers ripping the flyers down because they felt it was an intrusion of their private time. "Can't I even go to the bathroom without thinking about C++?"
But the Grouplet persisted. They realized that culture doesn't change through memos. It changes through "ambient awareness." If you see a flyer about unit testing every time you go to the bathroom for six months, you eventually start thinking about unit testing while you’re at your desk. It becomes part of the atmosphere.
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Mike Bland, one of the key figures in the Testing Grouplet, has written extensively about this. He notes that the goal wasn't just to teach a specific tool. It was to build a "test-certified" culture. They wanted engineers to feel a sense of pride in having a "green" build. The flyers were just the most visible part of a much larger effort that included "Testivus" celebrations and internal certification levels for different teams.
What a Real TotT Flyer Looked Like
You won't find a glossy, high-production value PDF here. The real flyers were sparse. They usually followed a predictable—but not rigid—pattern.
Typically, the top of the flyer featured a catchy headline. Something like "Don't Get Mocked" or "Small Tests, Big Wins." Then, a brief explanation of a problem. Let’s say the problem was "Flaky Tests." The text would explain that a test that fails 1% of the time for no reason is actually worse than no test at all, because it teaches the team to ignore failures.
Next came the code samples. This was the meat. They’d show a "Bad" version of a function—usually something tightly coupled to a database or a network—and then a "Good" version that was easily testable. They’d use real languages used at Google: Java, C++, or Python.
Finally, there was the call to action. It wasn't "please consider this." It was "Go do this now."
The Lasting Impact on Modern DevOps
While the physical flyers are less common now—mostly because Google is enormous and many people work remotely—the legacy of Testing on the Toilet is everywhere. It paved the way for the "Site Reliability Engineering" (SRE) movement. It proved that "Quality" isn't a department; it's a feature.
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When you use a tool like GitHub Actions or Jenkins today, and you see that little green checkmark next to your commit, you are seeing the result of the culture the Testing Grouplet fought for. They moved the "cost of quality" upstream.
Think about the math. A bug found during development costs almost nothing to fix. A bug found in production can cost millions and destroy a brand's reputation. By forcing engineers to think about testing during their "down time," Google effectively saved untold millions of dollars in technical debt.
Can You Do This at Your Company?
You might think, "I'll just print some sheets and stick them in the bathroom tomorrow."
Slow down.
The success of Testing on the Toilet wasn't just about the location. It was about the consistency. The Grouplet did this for years. They responded to feedback. They updated the content. If you try this at a 20-person startup, you might just look like a micromanager.
However, the core principle—Micro-learning in high-latency environments—is universal.
If you want to implement a version of this, you have to keep the "Edutainment" value high. If the flyers are boring, they become background noise. If they are too complex, they get ignored. They have to be the "Goldilocks" of technical content: just right for a three-minute sit-down.
Real-World Takeaways for Your Team
If you’re looking to improve your team's code quality, don't just buy a subscription to a video learning platform that nobody will watch. Start small.
- Focus on the "Why" over the "How." Don't just tell people to use a library. Explain why the current way of doing things is causing them pain (like those 2:00 AM pagers).
- Keep it visual. A diagram of a microservices architecture is much easier to digest than a wall of text.
- Rotate the content. Information becomes invisible if it stays in the same place for too long. Change your "Testing on the Toilet" flyers every two weeks.
- Acknowledge the absurdity. Lean into the joke. Use bathroom puns. It makes the "medicine" of learning new testing frameworks go down a lot easier.
The reality of software engineering is that we are all overwhelmed. We have too many tools, too many deadlines, and too much coffee in our systems. Testing on the Toilet worked because it respected the engineer's time by using the one moment of the day when they were actually forced to slow down.
Practical Steps to Start Your Own Culture Hack
- Identify your "Red" zones. What is the one thing your developers keep messing up? Is it forgotten error handling? Hard-coded secrets? Start there.
- Draft a one-pager. Write it for a smart friend who is tired. No corporate speak. No "synergy." Just code and logic.
- Find a physical or digital "Stall." If you're in an office, the bathroom or the kitchen works. If you're remote, maybe it's a dedicated Slack channel called #the-watercooler where you post a "Tip of the Week" image.
- Measure the "Vibe." You won't get a spreadsheet showing a 10% increase in code quality overnight. Look for the "TotT effect"—when you hear an engineer say at a meeting, "Hey, I saw that thing on the bathroom door, we should probably refactor this."
- Keep the barrier low. The moment this becomes a "task" or a "required reading," it dies. It must remain a gift of knowledge, not a chore.
Culture is what happens when no one is looking. Or, in this case, when everyone is looking at the back of a bathroom door. The Testing Grouplet proved that you don't need a budget or a title to change the way a multi-billion dollar company builds software. You just need a stack of paper, some tape, and a very captive audience.