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Functional Testing Types and its Benefits

Navdeep Singh Gill | 17 Oct 2022

Functional Testing Types and its Benefits

What is Functional Testing?

Functional Testing demonstrates a software system against its functional specifications and determines whether each application function works according to the software requirements.

What is Functional Testing in Software Testing?

  • It is a type of software testing in which a system is tested against functional requirements and specifications. Software testing executes a program or application to check whether the actual results match the expected results and to assure that the software system is Bug- free. It can be either done manually or using automated tools. Software testing is classified into two categories -

    • Functional Testing
    • Non - Functional Testing

    Functional Testing reviews every aspect of a piece of software to make sure that it works correctly. It verifies that the system should perform as expected when its features are exercised by some other system or directly by a user.

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What are the various types?

The common types of Functional testing are defined below:

Unit Testing

Unit testing should start at the very beginning to assure that each block of code/unit performs its intended manipulation of inputs into desired outputs for the next module. Tests an individual unit/component of the software to validate that each unit performs as designed.

Integration Testing

Takes multiple individual units/components of the software and tests them as a group to ensure that the unit modules connect as expected and convey data and commands throughout the system per the specifications built.

Smoke Testing

Smoke testing is a subset of test cases that tests the major/critical functionalities of software in a non-comprehensive manner to ensure the software works well enough to move on to additional tests. Execute before any detailed functional or regression tests are performed on the software build.

Sanity Testing

After receiving a software build, verify that minor changes and fixes applied to the code body do not have unexpected side effects in separate parts of the system and confirm that the bugs have been fixed. If sanity tests fail, the build will be rejected to save the time and costs involved in more rigorous testing.

Regression Testing

Verify that the later feature additions and bug fixes(due to which code changes) do not adversely affect existing features. Regression Testing is nothing but the complete or partial selection of already executed test cases that are re-executed to ensure existing functionalities work fine.

User Acceptance Testing

This is the last step before software goes live; user acceptance tests ensure it can handle required tasks in Real- World scenarios, according to specifications. End users typically perform these tests during the Beta testing period.

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What are the benefits?

Functional Testing has the following Benefits -

  • It ensures that the customer or end-user is satisfied.
  • It produces a defect-free product/software.
  • It ensures the all the requirements should be met.
  • It ensures the proper working of all the functionalities of an application/software/product.
  • It ensures that the software/product works as expected.
  • It ensures security and safety.
  • It improves the quality of the product.
  • The risks and losses associated with the product/software are reduced.


How does it work?

When conducting functional tests, you should typically need to follow a process that looks something like this -

  • Use test data to identify the inputs.
  • Determine the expected outcome based on those inputs.
  • Test cases with the proper inputs.
  • Compare actual results with expected results.

If the actual and expected results will match, then conclude that the software functions correctly and that the test has passed. If they do not match, the software has an issue.

Two Perspectives -

  • Requirements- focused testing, prioritizing requirements based on risk criteria first to evaluate the most critical and essential features and functions.
  • Business-process-focused testing relies on the knowledge of end-user business requirements to evaluate application performance in the context of use cases.

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Why Functional Testing Matters?

It can be simple to dismiss software testing as an unwanted investment of time and money. But for so many organizations, one minor bug spiraled out of control. Embarrassing software glitches in the product might make a brand go viral incorrectly. No requirement for the significance of proper software testing techniques the hard way.


Apple's recent iOS 11.1 updates came with a host of glitches. Users report that the new system did not type the letter "I," and emitted a cracking sound during phone calls, so they didn't buy iPhone 8.
Apple was not the only company to fail to deliver on a cell phone's most basic function this year. One of its competitors, the Android OnePlus 5, disconnects when users try to call 911.Removal of objectionable content from the news feed. Identity revelation on Facebook of the hater's group.
Timing anomaly in GPS causing a global GPS time delay of a whopping 13 microseconds, affecting users for several hours.
Delay in testing caused the release of BART's new fleet of train cars to be pushed back by several months, indicating the exterior of the new trams is good to go, but that performance monitoring may be holding up the process.

How to adopt it?

  • Black Box Testing
  • White Box Testing
  • Gray Box Testing

Black Box Testing

Black Box is a testing technique in which the software's functionality is tested without looking at the internal design/code/structure/implementation details and knowledge of the internal paths of the software. It examines the functionality of an application based on the specifications.

White Box Testing

White box tests are predicated on knowing precisely about code/structure/implementation under test and tests executed to verify the robustness of the code than its complete functionality. It is performed at the beginning of the development process with unit tests and in the early parts of the integration phase. Black box testing is typical of the latter stages, where a response to specific operating scenarios is essential.

Gray Box Testing

The third type of testing is a combination of a White and Black box. Gray Box Testing happens as development moves into a crossover zone towards the end of integration and the beginning of usability. A gray box is a device, program, or system whose workings are partially understood.

Unit testing operates on a low level and is tightly coupled with source code. Click to explore about, Golang Unit Testing

What are the best practices for Functional Testing?

Any functionality is tested by providing inputs, observing its output, and comparing the actual results with the familiar ones. Here are some effective procedures or best practices that may come in handy while you perform functional testing -

Reusable test cases

Developing test cases may take time, so the more reusable you can prepare test cases, the better. While writing reusable test cases, write in a simple language that is easy to understand and the test steps short and easy to execute. Then, help to reuse test cases when appropriate rather than reinventing the wheel each time, be sure to stay organized by managing those test cases in a single source of truth like a test case management tool.

Test data and configurations drive design tests

Relying on test data and configurations to develop test steps will ensure you have everything you need to complete the tests and fully understand the results. For example, have the proper login credentials to access all of the functionality to test and ensure correct input data because it will impact whether a test will pass or fail. Pay close attention to testing the data and configurations at each step. These details are essential when informing developers and product owners about and understanding the causes of those issues.

Prioritize high-risk and complex test cases

When it comes to manual testing, prioritize complex risk and high test cases, as these are the ones that most need a human at the steering wheel.

Consider opportunities for automation.

Although don't automate all of the testings, look for opportunities to embrace automation to save time and make it easier to run specific tests more often. Remember to take an automated first approach when considering which tests are best to execute manually and which tests are more suitable for automation. Keep the complexity on top of mind.

Don’t overlook the importance of documentation

Documentation is a critical piece of manual testing, especially when it comes to tracking the issues through reports. A good report is essential to help others on the team (testers and developers alike) understand what problems exist and how to find these issues. To make a strong report, an ordered list of steps to recreate the problems that are much easy to understand and follow, details on the basis severity and priority of the issue, and insight on what should happen if the issue is resolved.

Java vs Kotlin
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What are the best tools for it?

In the era of automation, applications are developed specifically for the work done quickly and efficiently. Highly dependent on minimizing work efforts with the help of various tools.
There are varieties of tools available for testing. Just type "test tool, and find a wide range of answers, from open source to best of the breed—based on many different assumptions. Various types of Functional Testing Tools are -

Compressive Strategy

Creating a highly-scalable and cost-effective software helps companies to Increase business efficiency. For making immediate decisions based on automation and testing, we advise taking the following steps