Everything You Need to Know About Software Testing Methods

Focused software tester working at laptop in office
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Before software ships for public or commercial use, programmers spend hours ironing out every bug, with the product remaining in limbo until all stakeholders are satisfied.

Silicon Valley software giants like Google and Facebook will often ship popular products to market despite their software's low-priority bugs. Investors and millions of loyal users will tolerate software updates and temporary kinks in products these companies offer.

Most software companies don’t have this luxury. Customers want products to perform as advertised and are rightfully alarmed if there are unaddressed vulnerabilities.

Why Are Testing Skills Necessary?

With so many software development options available, customers don't think twice about jumping ship if the product stinks of wasted time and money. Software businesses must perform rigorous testing on their products before releasing them to customers. These tests offer the following insights:

  • They highlight differences between the original concept and the final output.
  • They verify that the software works as the designers planned.
  • They assess features and quality.
  • They validate that the end product meets customer requirements.

Testing follows a strict blueprint to optimize workload, time and money while providing stakeholders with essential information to move the product forward. The goal is to facilitate a positive end-user experience by keeping a thorough quality assurance (QA) program. Given the high stakes for developers, QA managers are some of the top earners in the technology industry. Testing usually follows these steps:

  1. Conduct a requirement analysis, where managers outline a plan to put a suitable test strategy in place.
  2. Begin tests and analyze the results.
  3. Correct any defects and put the software through regression testing (a system to check that the program still works after modifications).
  4. Create a test closure report detailing the process and outcomes.

Individuals can become certified software testers through BCS, The Chartered Institute for IT, ISTQB (International Software Testing Qualifications Board), and ASQ (American Society for Quality).

Software Testing Methods

Black and white box testing are two fundamental methods for judging product behavior and performance. Black box testing, also called functional or specification-based testing, focuses on output. Testers aren’t concerned with the internal mechanisms. They only check that the software does what it’s supposed to do. Knowledge of coding isn’t necessary, and testers work at the user-interface level.

White box testing uses coding experience as part of the test procedure. When a product fails, testers go deep into the code to find the cause. Software developers will do this themselves because clients expect them to make a product work. White box testing is also referred to as "structure-based" or "glass box" testing.

Static testing examines the source code and any accompanying documentation but doesn’t execute the program. Static tests start early in the product’s development during the verification process.

Dynamic testing uses various inputs when the software is running, and testers compare outputs with expected behavior. Graphical user interface testing evaluates text formatting, text boxes, buttons, lists, layout, colors and other interface items. GUI testing is time-consuming, and third-party companies often take on the task instead of developers.

Test Levels

Different testing levels are used to identify areas of weakness and overlap in each phase of the software development lifecycle. The test levels are:

  • Unit test
  • Integration testing
  • System testing
  • Acceptance testing

When unit testing, developers test the most basic code parts, such as classes, interfaces, and functions/procedures. They know how their code should respond and can make adjustments depending on the output.

Integration testing is also known as "module" or "program" testing. It’s similar to unit testing but contains a higher level of integration. Modules of the software are tested for defects to verify their function. Integration testing identifies errors when the modules integrate. Different methods for integration tests include "bottom-up", "top-down" and "functional incremental".

System testing tests components of a project as a whole in different environments. System testing falls under the black box method and is one of the final tests in the process. It will determine if the system is prepared to meet business and user needs.

There are generally two type of acceptance testing. In alpha testing, the software is executed internally at the developer’s site in a simulated or actual environment. The software runs as if live end-users were using it. Developers make notes of any issues and begin to rectify bugs and other problems.

Also under the scope of black-box testing, in acceptance testing, clients test software to find out if the developer has fully developed the program to fit their desired specifications.

Beta testing, or field testing, lets clients test the product on their sites in real conditions. Clients may offer a group of end-users the opportunity to test the software via pre-release or beta versions. Beta testing aims to get actual user feedback, which is sent to the developer.

Test Types

Different types of software tests are designed to focus on specific objectives. The test engineer and the configuration manager use installation testing to ensure the end-user can install and run the program. It covers areas like installation files, installation locations and administrative privileges.

Developmental testing implements a range of synchronized strategies to detect and prevent defects. It includes static code analysis, peer code reviews, traceability and metrics analysis. The aim is to reduce risks and save costs.

User experience comes under the spotlight with usability testing. It measures how easy the GUI is to use. It checks the accuracy and efficiency of functions and the emotional responses of the test subjects.

A sanity test indicates if the software is worth the time and cost to continue further tests. If there are too many flaws, more aggressive tests won’t follow.

Sanity testing is done during the software release phase, where smoke testing is done to see if the software will run enough to be testable.

Smoke testing reveals fundamental failures that are serious enough to prevent release. When developers test a new build, it is called a "build verification" test. When the system undergoes modification, regression testing monitors unexpected behavior. It points out adverse effects on modules or components.

Testers input abnormal entries and discern the software’s ability to manage unexpected input in destructive tests. This shows developers how robust the program is at error management.

When hardware or other functions fail, recovery testing shows how well the software can recover and continue operating.

Automation performs functions that are challenging to implement manually. Testing involves using specific software to run tests and provide data on actual vs. expected outcomes.

The software must run in various computing environments, so compatibility testing checks how the software responds to different systems. For example, programmers test the software with various operating systems and web browsers.

Tests must be extensive and address all client concerns, or the project quickly becomes a waste of resources.

Performance testing examines software performance in different scenarios. Information about responsiveness, stability, resource allocation and speed is gathered. Sub-tests such as volume, capacity and spike testing play a part in this process.

Security testing measures the software’s ability to protect users’ security. Authorization functions, authentication, confidentiality, integrity, availability and non-repudiation are all examples of features that must be tested.

Accessibility testing is different than usability testing. This determines the extent to which users of various abilities can use the software.

Internalization and localization test results show how the software can adapt to different languages and regional demands. This includes adding components for specific locations and text translation.