Testing isn’t a technical checkbox. It’s a strategic decision that can shape the entire lifecycle of your product. But if you’re a business owner, product lead, or CTO planning your next release, figuring out what kind of testing your project actually needs can feel overwhelming.
Do you go with manual or automated? Focus on functional bugs or stress tests for scale? Is a beta test necessary or risky? And how do you avoid wasting time and budget on testing methods that don’t move your product forward?
We recently sat down with Aliaksandr Shabanau, an experienced PHP developer and a Drupal contributor, to explore these questions. What followed was a deep technical conversation — not just about test types and terminology, but also about how businesses can make better decisions by understanding their project context.
“There’s no universal formula. Testing choices should come from your goals, risks, and how your product is going to live in the real world,” Aliaksandr explains.
This longread aims to unpack that complexity. We’ll explore the major types of testing — from functional to non-functional, alpha to beta, manual to automated — and explain how each one fits into different kinds of projects. We’ll also touch briefly on the business side: what questions you should be asking before deciding how (and how much) to test.
Why the right type of testing matters
Let’s start at the root: why does choosing the right test type even matter? Isn’t it enough to make sure things “work”?
Not really. Different kinds of tests reveal different kinds of risks. A basic functional test might confirm that your checkout button submits an order, but it won’t tell you what happens when 10,000 people click it at once. Or whether hackers can exploit that form. Or if the experience is confusing for users on older devices.
“One type of testing might validate that a feature exists. Another will tell you if it actually survives in production,” he points out.
In short, the type of testing you choose will shape what you discover and what you miss.
Functional vs. non-functional testing
At the highest level, software testing splits into two broad categories: functional and non-functional.
Functional testing checks whether your system behaves according to expectations. That includes verifying inputs, outputs, and use-case flows. If your app is supposed to calculate a price, route a delivery, or display a dashboard, functional tests ensure it does exactly that.
“Functional testing is your baseline. It tells you if the product does what the spec says,” Aliaksandr notes.
But it doesn’t end there.
Non-functional testing dives deeper. It explores how the system performs under pressure. Is it fast? Is it secure? Can it scale? Will it remain usable on a mobile browser or in a slow network environment?
“We’ve had clients say, ‘but the feature works.’ And yes, it works — until 2,000 users hit it at once. That’s when the problems start,” he emphasizes.
Think of it this way: functional testing checks whether your car engine starts. Non-functional testing checks how it performs on the highway.
Manual vs. automated testing
Now let’s talk about how testing happens.
Manual testing is performed by human testers who interact with the software as end users would — clicking through the interface, submitting forms, navigating workflows, and spotting issues.
It’s flexible, adaptable, and easy to start with. But it doesn’t scale well. Regression testing — repeating the same checks again and again — gets time-consuming fast.
That’s where automated testing comes in. Here, developers write test scripts that simulate interactions and validate outcomes programmatically. These tests can run anytime, with no human oversight.
“We always recommend automation for growing projects. But it only makes sense when your product is stable enough to support it,” he advises.
Automation shines in large or long-term projects. And for Drupal-based systems, many tools and test frameworks are already available out of the box, making it easier to build robust pipelines. If you’re curious how we approach this at Attico, take a look at our Drupal testing services.
Still, manual testing has its place, especially during early-stage development, UI changes, or exploratory sessions.
“There’s value in having a human click around and say, ‘this feels wrong,’” Aliaksandr observes.
Regression testing: what it is and why it matters
There’s a specific category of testing that becomes crucial once your product reaches maturity — regression testing. It ensures that new features or fixes haven’t broken anything that used to work.
It might seem like a non-issue — until it isn’t.
“I’ve seen teams push a hotfix and accidentally disable a completely unrelated part of the site. Regression tests would’ve caught it,” Aliaksandr says.
Automated regression tests are especially powerful. Once you’ve built a reliable test suite, you can run it every time new code is pushed. This makes it far easier to ship frequently without fear.
Manual regression testing, on the other hand, is time-consuming and prone to inconsistency, particularly if the product is large or frequently updated. That’s why many teams treat regression as one of the first areas to automate.
“The more often you release, the more important regression becomes. You don’t want to break your checkout flow just because you updated the homepage,” Aliaksandr adds.
Regression testing is not about finding new bugs — it’s about keeping old bugs from coming back. And it’s often the quiet hero of a stable product.
Alpha and beta testing: when to open the gates
Let’s talk timing. Specifically, the role of alpha and beta testing.
Alpha testing happens internally. It’s when your dev or QA team tests the product in-house, often before any customer gets their hands on it. It’s private, controlled, and usually involves access to code and logs.
Beta testing invites real users — often in a public or semi-public setting — to try the product in real-world conditions.
“Alpha tests tell you if the product works. Beta tests tell you if people can and will use it,” he remarks.
The biggest benefit of beta testing is environmental diversity. Your QA team might use five browsers and two phones. Your users might use twenty. They might also do unexpected things, like refreshing at the wrong time, entering an emoji in a name field, or trying to log in with an expired link.
All of these behaviors expose edge cases you wouldn’t find otherwise.
However, beta testing isn’t always feasible. Products involving sensitive data — banking, healthcare, or enterprise dashboards — may need to stay closed until thoroughly validated.
“In fintech or medtech, you don’t want beta users finding bugs. You want zero surprises,” Aliaksandr warns.
Black-box, white-box, gray-box: a matter of access
Another axis of testing is how much the tester knows about the internals of the system.
Black-box testing simulates the real-world user experience. The tester doesn’t see or rely on the code. They interact with the system solely through the UI or API.
White-box testing is code-aware. It inspects logic, control flow, edge conditions, and internal state.
Gray-box testing sits in the middle. The tester knows some of the implementation details but still tests externally.
“Black-box tests reflect reality. That’s how users experience the product. But white-box tests catch the deep bugs — stuff a user could never explain,” he clarifies.
In many real-world projects, you’ll end up using a combination. For example, your team might write white-box unit tests for backend logic and perform black-box exploratory testing on the UI.
Some constraints also dictate the method. If you’re reviewing a third-party app without code access, black-box testing may be the only option.
Testing third-party integrations: where control ends
In today’s stack, few applications are fully self-contained. Payment gateways, social login, analytics, content feeds — chances are, your system depends on at least one external API. But testing those connections introduces a new challenge: you don’t own the code.
“We’ve had projects where the feature worked perfectly until the third-party API changed,” Aliaksandr recalls.
When working with third-party services, you often rely on black-box assumptions. You don’t know how they handle edge cases, scale under load, or deal with malformed requests. That makes error-handling and fallback flows even more important.
“If their system fails, you need to fail gracefully. That’s part of your responsibility, even if the root cause isn’t on your side,” he emphasizes.
In QA, that means mocking external responses, testing timeouts, and simulating partial failures. You may not be able to control the external system, but you can control how your product reacts when it fails.
For critical integrations like payment processors or identity providers, this testing is non-negotiable. It’s not just about stability. It’s about trust.
Component, integration, and system-level testing
Now let’s zoom out from methods to structure.
Most test strategies align with three scopes:
Component tests focus on a single unit of logic (like a function or class).
Integration tests check how multiple components interact (for example, a payment processor + notification service).
System tests verify that the full application behaves correctly end-to-end.
“People sometimes test all 50 modules at once. When something breaks, they have no idea where to look,” he recalls.
Instead, the expert recommends incremental integration testing. Group related components and validate them together. That way, when something fails, you’ve narrowed the problem space dramatically.
Positive and negative testing
Not all bugs come from systems failing to do what they should. Some happen when users do something the system shouldn’t allow.
That’s where negative testing comes in.
Positive tests validate correct behavior: entering valid inputs, following expected flows, and confirming good results.
Negative tests simulate mistakes or malicious behavior: entering letters where numbers belong, submitting empty forms, or trying to bypass authorization.
“If someone enters ‘hello’ in a calculator field, the app shouldn’t crash. Even if it’s a misuse, you still need to handle it gracefully,” Aliaksandr stresses.
Good testing covers both sides. But too many teams stop at the positive path and pay for it later.
Edge case testing: when things get weird
Even if your app passes every positive and negative scenario, that doesn’t mean you’re safe. Enter: edge cases — those strange, rare, or extreme situations that few users hit, but which can still break your system.
Think 300-character usernames. Emoji-laden form fields. Logging in on a smart fridge. Or submitting a form precisely at midnight GMT.
“Edge cases are where the weird stuff lives. You can’t test for everything, but you can test for the ones that matter,” Aliaksandr explains.
Not all edge cases are worth pursuing. But if your product serves a wide or global audience or has financial, legal, or accessibility implications, you can’t afford to ignore them.
Good QA includes a mindset for identifying edge risks. What’s the longest possible input here? What happens if I hit backspace 100 times? What if the user has no internet for 0.3 seconds?
“Testing for edge cases is about defensive thinking. It’s asking, “What’s the most inconvenient way someone could use this and does it still hold up?” he says.
When there’s no documentation: testing with intuition
Early-stage products, prototypes, and MVPs don’t always come with a clear spec. That makes traditional requirement-based testing difficult.
But experienced testers can still spot issues by relying on intuition and user empathy.
“I might see a button that looks like it deletes something, but it doesn’t say what. That’s a problem, even if the code is technically fine,” he remarks.
This approach is especially useful in startup environments, where the product is evolving quickly and user experience matters more than formal correctness.
In these cases, hiring testers who understand real-world usage, not just test automation tools, is critical.
Picking the wrong test framework: a preventable headache
One of the more avoidable mistakes we see? Teams are choosing the wrong testing framework too early.
“We’ve seen projects start with Behat for behavior tests, but then hit a wall. Their needs grew, and Behat couldn’t scale with them. So they had to rewrite in PHPUnit,” he recalls.
The problem isn’t with Behat — it’s about choosing a tool based on today without considering tomorrow.
Framework decisions should reflect long-term goals. Do you plan to scale? Will you need cross-platform support? Will your team grow and need maintainable test suites?
If you’re building with Drupal, that gives you a head start — its core is already wired for scalable PHPUnit testing. But for custom stacks or microservices, think carefully before committing to a toolset.
Business context: what to ask before testing starts
Even if your main focus is technical coverage, testing decisions should always be tied to the business goals of the project.
Before you start testing, ask yourself:
What kind of product is this? (Web, mobile, embedded?)
Is it an MVP or a mature system?
Will it process personal or financial data?
Is accessibility a requirement?
What browsers, devices, or networks does it need to support?
Will we maintain this product over months or years?
Who will be responsible for updating the tests over time?
“If your site needs to meet accessibility standards, that changes how and what you test. And if you’re using Drupal, you already benefit from a strong foundation,” Aliaksandr adds.
Budget also matters. Testing a fintech app is not the same as testing a blog. Neither is wrong, but one needs more planning, documentation, and long-term QA investment.
Post-launch maintenance is another important factor. If you expect to iterate and release regularly, you’ll need tests that can evolve with the codebase.
How to build a healthy test culture
Even the best tools and frameworks can fail if testing is seen as an afterthought. That’s why building a test culture, where quality is a shared responsibility, is just as important as any methodology.
“Testing should be part of the conversation from day one. Not something you add at the end,” Aliaksandr remarks.
A healthy test culture includes developers writing tests alongside features, product managers thinking about edge cases during planning, and QA teams empowered to challenge unclear specs.
It also means normalizing failure, not as a setback, but as a signal.
“If a test fails, that’s not bad news. It’s useful information. It means something changed—and now you know,” he says.
When testing becomes a habit rather than a hurdle, your whole team moves faster, with more confidence.
Final thoughts
Choosing the right type of testing isn’t about picking a tool off the shelf. It’s about understanding your product, your users, and your risks and making thoughtful decisions from there.
There’s no one-size-fits-all. But there is a best-fit approach for your specific case.
“Think long-term. Make decisions that won’t just work today, but also scale tomorrow,” Aliaksandr concludes.
And if you’re not sure where to start? Don’t guess. Work with a team that can help you assess your needs, evaluate your risks, and design a testing strategy that grows with you.
That’s what we do at Attico. From audits to automation to long-term maintenance, we help teams build better software, one test at a time.
Author: Aliaksandr Shabanau, PHP Developer at Attico
Aliaksandr is a PHP developer at Attico, a Drupal company headquartered in Vilnius, Lithuania. He is an active contributor to the Drupal community, passionate about clean architecture and autotests.
Read more:
How to Choose the Right Type of Testing for Your Project
