Software Testing Basics: Types of Bugs and Why They Matter?


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Coming up with brilliant software solutions requires lots of software testing basics and freaking. You are bound to come across error messages and another development roadblock throughout this process. When you know the different types of software testing basics for beginners you are likely to encounter, you will also know the best approaches to fix them.

To make the detection and prioritization of defects faster and easier, it is recommended to apply rigorous classification techniques. Below we have tried to outline the approach to classified software bugs and listed some of the most common bugs accompanying them with examples.

Software testing basics: Three common classifications of software bugs

Software bugs could be classified in three ways: by nature, by priority, and by severity. While the classifieds for the latter two are present in bug tracking systems by default, it is recommended to set up a classifier for the division of marks by their nature as well, since it helps in streamlining the assignment of bugfix in tasks to responsible teams.

Below are the software defects by nature:

Functional defects

If the behavior of software isn’t submissive to functional requirements. Search types of defects are identified by functional testing. For instance, a functional fault was identified in a search engine for an eCommerce website in one of our latest test projects. When a user put in a product ID, it did not return any results, while requiring that the search be performed with both the name and the product ID.

Performance defects

Performance defects are linked to the velocity, stability, reaction time, and consumption of resources of the program and found during performance testing. The reaction time of the system X times greater than that specified in the specifications is an example of a performance fault.

Usability defects

Deficiencies in usability make it difficult to utilize an application and hence hinder a user's software experience. The usability flaws are instances of an excessively complicated content layout that is difficult to read or browse and a signup method. To discover these problems, test engineers and business analysts (or UX designers) assess software against usability and WCAG during usability testing.

Compatibility defects

A compatibility error application does not demonstrate consistent performance on specific types of hardware, operating systems, browsers, and devices or when linked with certain applications or running under certain network settings. To find out such problems, compatibility software testing basics are carried out. 

For example, it has been found while testing a mobile application for estimating vehicle insurance claims, it failed to meet Android 8.0 and 8.1 standards. The deficiencies were linked to font size, text alignment, and scroll bar modifications.

Security defects

The vulnerabilities that allow a possible security assault are safety shortcomings. Crypton problems, SQL injection sensitivities, XSS vulnerabilities, buffer overflows, poor authentication, and logical faults in role-based access are the most prevalent security defects of projects software testing basics interview questions.

Defects according to severity are based on the technical impact a defect has on a system and single out of the following severity levels. Below are the software defects by severity:

  1. Critical defects block an entire system on module functionality and software testing basics interview questions will not proceed further without such a defect being fixed.
  2. High severity defects affect the functionality of an application and the app will behave in a way that is strongly different from the one stated in the requirements. For example, an email service provider won't allow adding more than one email address to the recipient field.
  3. Medium severity defects are identified in case a minor function doesn't behave in a way stated in the requirements. A broken link in an application's terms and requirements section is an example of medium severity defect. 
  4. Low severity defects are primarily related to an application’s user interface and can include such an example as a slightly different size or color of a button.

Defect priority will characterize an error’s business impact. In various projects, a project manager, product owner, or any business stakeholder can identify defect priority. Below are some of the priority levels:

  1. Urgent defects should be fixed within 24 hours after being reported. Defects with the critical severity status fall into this category. Nevertheless, low severity defects can be classified as high priority as well. For example, a typo in a company's name on an application's home page doesn't have a technical impact on software but will have a major business impact, hence it will be classified as urgent.
  2. High priority defects are errors that should be fixed in an upcoming release to meet the exit criteria. An example of a high priority defect is an application failing to navigate a user from the login page to the home page even though the user has entered valid credentials.
  3. Medium priority defects errors that can be fixed after an upcoming release or in the subsequent release. An example of a medium priority defect is an application returning the expected result which, however, formats incorrectly in a particular browser is
  4. Low priority defects are errors that don't need to be fixed to meet the exit criteria but need fixing before an application becomes generally available. Typos, alignment, element size, and other cosmetic user interface issues are usually included in this group.

Why does correct defect classification matter?

After learning how to classify defects, you will ensure that not only the responsible project teams are given problem handling but you will also simplify the defect priority setting. It thus accelerates the fixation of defects and improves the overall efficiency of testing and development operations.

As the severity of defects and priority levels impact the assessment of the effectiveness of the development process and may influence payments and punishments in outsourcing development, defining criteria to evaluate the severity of defects and priorities for your project is essential.


As noted previously, perfect software testing basics for beginners have to be tested extensively, debugged, and optimized. Whatever the problem type, testers must guarantee that most bugs are found and handled in the early stages, to ensure that rework is not reworked in later stages. Developers may assist avoid mistakes in the development process with clarity on typical sorts of problems.

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