Testing Types Explained: Which, When, and Why?

Published on May 15, 2018
Testing Types Explained: Which, When, and Why?
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Do you believe in love at first sight? When it comes to software, it is usually the case: you either like it and keep using it or delete the buggy thing. That’s why it’s so important to test your software before launch thoroughly. The numbers prove it: according to recent research, 67% of consumers will churn after a bad experience. On top of that, 47% of respondents will quit an app if at least one product image doesn’t load. Ouch.

Poor user experience and errors rate higher than you may think. That’s why proper quality assurance (QA) isn’t an option; it’s a sensible investment. But what exactly should you inspect when testing a mobile app, a website or any other kind of software? Let’s take a look at different types of testing and see when you should use them.

Everything You Need to Know About Testing

Testing software might sound simple. But in reality, quality assurance has to be run by trained professionals who know where the peskiest of bugs are hiding. Manual or automated, integration, performance, usability – there are dozens of testing types QAs and software developers have to be familiar with. And so will you after reading this article.

Manual vs. Automated Testing

You’ve probably heard that software testing can be manual and automated. Just as the name suggests, manual testing requires QA specialists to click through the software. Automated testing, on the other hand, is done by a computer, but that doesn’t mean that no human help is needed. In fact, automated testing engineers write test scripts, do all the preparation and setting up while the machine only does the routine work.

In manual testing, the QA engineer is the one who sets up the testing environment. This can make the process lengthy and prone to human errors like typos or sloppy test execution. Automation can make the testing process faster; the scripts can cover multiple tests simultaneously on a wide variety of devices, but you will need some specialized tools to execute them.

Manual testing is used to test the user interface, user acceptance, security and basically all critical parts of healthcare, military, space, media or IoT software. Unit, functional, regression, integration, stress testing are better suited for automation.

Unit Testing

Unit tests verify individual sections of the code – units, to check if they function as needed or expected. A unit can stand for anything from a small button to an entire feature. It helps to make sure that particular code blocks can function independently and then work as a whole system.

Surprisingly, it is not the tester who writes unit tests. They are the sole responsibility of software developers. Programmers write unit tests for the source code using a bunch of helpful tools and frameworks.

Integration Testing

The next logical step is to ensure all units work well as a system. This is a job for integration testing and its approaches: top-down integration testing, bottom-up integration testing and sandwich testing. They detect the flaws in the cooperation between coordinated software modules and verify that all components work together correctly.

Functional Testing

Every piece of software should have a set of use cases, requirements and design documents. Functional testing makes sure a piece of software includes all the necessary functionality, specified in these documents.

Some may mistake functional for integration testing. The difference is that integration tests verify if it’s possible to query a database, while functional tests check if a database responds as required. Functional testing is responsible for the business constituent of your software, verifying the action value and not the state of the system.

Performance Testing

Sure, users want an app to be highly efficient and responsive, but they also need the piece of software to be stable. Performance testing will help you verify that your software is fast, reliable and scalable, as well as check if it can withstand peak loads and handle large amounts of users or data.

This testing type will help you eliminate performance bottlenecks and make sure you release a stable and robust application. Running performance tests allows you to deliver a high-speed application, website or product and meet customers’ expectations of a seamless user experience.

Regression Testing

Every time you add new modules and components or make any changes to the system, you need to check they don’t modify or ruin the existing solution. To verify that no functionality updates will produce unexpected errors, you have to run regression tests. Plus, with regression testing, you can also assess the existing features to detect new risks and issues.

Compatibility Testing

Rolling out software that lacks compatibility with various devices, operating systems or browsers is a road to nowhere. That’s when compatibility testing comes in handy, allowing you to fix the app’s functionality according to the target environments. If your application is designed to run on different application or web servers, databases, processors, hardware peripherals, etc. make sure to perform lots of compatibility tests.

​Usability Testing

One of the most critical steps on the way to launching successful software is to check if your end-users can easily interact with it. Manual usability testing is the key to checking exactly how user-friendly the GUI is. Run by actual users, usability tests help you find out if your application’s UI is smooth, clear and effortless to use. And let’s not forget that apps need to comply with ISO-9126, ISO-9241-11, ISO-13407 and other standards to prove their usability.

Security Testing

With the rapid evolution of technology, digital crimes evolve twice as fast. That’s why cybersecurity is not something to trifle with. Security testing will help you identify vulnerabilities and malfunctioning on the initial stages of the software development lifecycle and protect the critical system features from malicious attacks. Security tests will also help you prevent data leaks and hacker penetrations in post-production, allowing customers to be confident in your software.

Exploratory Testing

If there’s a testing type that offers full, genuine freedom to the tester, it’s exploratory testing. Without any documentation or preliminary planning, the QA engineer tests the piece of software to verify its overall quality. The trick is in the tester’s skills, experience and ability to invent test cases and find bugs “on the go.”

UI Testing

You might think of user interface testing as a trivial job. Isn’t it just checking the GUI against specifications? Well, a QA has to make sure that the element sizes, positions and colors correspond to the design documents; the style of the icons is correct and the fonts are readable; the error, warning or success messages are shown correctly; UI elements stay in their positions regardless of the screen resolution and so much more! Something that seems so simple actually requires a lot of professional testing. That’s why you just can’t afford to ignore UI testing.

Negative Testing

Don’t think of software testing as tedious and monotonous work. It is a process that also requires creativity. Take negative testing, for example. Sometimes referred to as error path testing or failure testing, negative testing checks the stability of your software by validating it against invalid data. This means thinking of as many exceptions as you can and feeding them to the system to see how it handles unscripted user behavior. Does it accept the data, show an error message or crash? Negative testing helps you find that out before a curious user does.

Localization Testing

The population of the Earth is wonderful in its diversity. So, if you’re targeting worldwide with your software, you need to pay proper attention to localizing it. Localization testing will help you make sure all the cultural and linguistic peculiarities of a particular locale have been taken into account, including the language, the font, the date and time formats and more.

A great app is a thoroughly tested app. There are many types of testing out there; we’ve briefly covered some of the most important of them. The more testing types you use to verify the quality of your software, the higher is the chance that the users will love it. The combination of excellent performance, functionality, compatibility with other systems, usability and security is exactly what will make your application stay ahead of the competition. And if you need help with software testing, you can always contact pwrteams TestLabForApps.


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