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The Most Common Software Bugs to Test For

Bugs are the common cold of the software world: recover and move on, but everyone has to go through it. In order for you to put out a project that you can be proud of, anomalies and errors in code have to be identified, recorded, and resolved.

Read on for information on the basics of what different types of bugs you will come across and so you’ll know the best way to approach them.

Unit level bugs

The most common bug, unit-level bugs are defects within the smaller batches of code. Often overlooked in the coding stages, they are also the simplest to fix. A unit test will divide an entire system into smaller units to check its source code.

Combing through smaller batches of code will make mistakes easier to see and replicating them is a simple process that won’t take too much time.

For these reasons, it is considered the very first level of testing and the foundation for other levels of testing. And fixing a bug early will mean less money down the line.

There are many automated tools to help make this testing go in smoother. Try NUnit or JMockit.

Functional bugs

Functional bugs are defects that affect the core functions and features of the app. For example, a retail app with no payment option has a functional bug. For more common bugs look at buttons that won’t submit a form, a search bar that won’t react to user input, or app crashes.

These bugs are hard to determine from customer behavior so test elements in seclusion or in combination with other features to spot differences. An educated guess can be made on thinking about what the customer was trying to do and what options are presented on how they can do it.

Consider tools like Selenium or Micro Focus UFT. If the function is still a problem, consider a workaround: an alternate route or option.

Logical bugs

Usually, due to poorly written code or misinterpretation of business logic, logical bugs cause disruptions to the software, causing it to act not as intended.

Think of NASA’s lost spacecraft due to a lack of conversion between British and American units. Things like assigning a value to the wrong variable can result in odd software behavior and even sudden crashes.

Notoriously difficult to track down, logical bugs can be weeded out by fuzz testing, which sends malformed inputs into targets, exposing crashes, infinite loops, and memory leaks. You can find out more about fuzz testing at

Workflow bugs

Workflow bugs cause a disruption to the flow or navigation of the user.

For example, a payment function will go through several pages, often with “next” at the bottom and if that “next” button goes back to the start, exits the process, or does anything except take the user to the next page, the flow of the application is ruined, causing a workflow bug.

Luckily these bugs can be quite obvious and will be reported if the application launches with them, so finding them isn’t too much of an issue. Manual testing can be enough to find problems in the navigation of your app, if tracked well.

System-level integration bugs

System-level integration bugs can be summed up in one word: miscommunication. Mostly found when two or more units of code are written by different developers, they will clash or fail to interact.

Examples of such mistakes can be overflow issues and inappropriate interfacing between the UI and the database.

They are harder to fix because you’re dealing with more than one piece of software, so they are also harder to find because visibility decreases as the size of the software increases.

Try to avoid byte-swapping or message parsing so as to not get too many and use a bug tracking tool like Backlog or Katalon TestOps to keep track of who’s doing what between testers.

Out of bound bugs

Out of bound bugs are bugs that have been caused by the user, usually by using something for an unintended use. Things like typing a number where a letter should be will cause a bug. They are most often found during functional testing of web or mobile apps.

Syntax errors

Inside the source code of the program, a syntax error will prevent the program from being properly compiled, usually due to missing or incorrect characters in code. Because we are all guilty of typos, this type of bug is very common, but it is also very easy to find.

Compiling programs will usually indicate where a syntax error has occurred so it can be fixed.

As part of the software development life cycle, fixing bugs is a vital part of creating a healthy application. If you keep a lookout for all these anomalies you might just put out a perfect piece of software.

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