A Deep Dive into Functional Testing | What Is Functional Testing ?

 

Functional Testing:

Functional testing is an important part of software testing, which ensures that the system meets its functional requirements and specifications. It assures that the application handles these issues correctly. This testing approach primarily analyzes the results of system operation, simulating real-world applications without making any assumptions about system design. Let’s find out what’s important in functional testing.

What is functional testing?

Basic functional testing confirms that each function in a software application performs according to specified expectations. This test does not go deep into the source code of the application; Instead, it evaluates each implementation by comparing results to expectations and providing relevant test data. This includes a variety of features such as user interfaces, APIs, database services, security policies, and overall application services. Functional testing methods can be both manual and automated.
Functional testing is one of the most important types of testing that is used in the evaluation of software; it involves the testing of a software function in an effort to ensure that it runs as required. It involves exercising the application’s functions to check whether they work as intended for a specific testing phase. 

Key aspects of functional testing:

The Functional testing concept means testing of functions or features of an application where it is the procedure of examining numerous features of an application in a systematic and effective way.
  • Purpose: Verifies that the application exhibits the expected behavior in every function based on the  parameters set during the creation process.
  • Scope:
    • Black-Box Testing: That is usually performed without the awareness of the internal arrangement of the software or without even the slightest understanding of the written code behind it. During testing, testers run various functionality tests to check how the software reacts during API or GUI operations.
  • Types of Tests:
    • Unit Testing: Ensures that an individual unit within the system is working correctly before combining it with other elements.
    • Integration Testing: Tests if the components of an organized system running together are performing their expected function.
    • System Testing: Considers full as well as whole end-to-end system of the software to assess if it meets certain predetermined criteria.
    • Acceptance Testing: Concludes the finality of the needs of the business and whether the software developed is fit for use.
  • Testing Techniques:
    • Input-Output Testing: Uses sample data to input in to the software and checks the outcome against expected outcome or actual results.
    • Boundary Value Analysis: Checks how the program performs on the margin of acceptable entries to determine if the software correctly responds to cases that are on the borderline.
    • Equivalence Partitioning: Apportions input data into partitions such that each data class is contained in an equivalent number of partitions to minimize the number of test cases without compromising on completeness.
    • Error Guessing: In line with this rationale employed by testers relies on experience and intuition whereby the tester embeds known errors into the system in the hope that other problems will be revealed.
  • Tools and Automation:
    • Selenium: Well known web app testing tool, enables API and cross-browser testing and therefore can function on any platform.
    • JUnit and NUnit: Java and .Net are also the more common frameworks for unit testing. NET environments, respectively.
    • Postman: API testing tool employed for executing functional test cases of an API.
  • Benefits:
    • Improved Quality: Ensures that defects are recognized before the later cycles of development happen which makes the expenses and time to correct the problem areas less.
    • Customer Satisfaction: Confirms that the software will perform the planned functions, and will be utilized as a user expects.
    • Risk Mitigation: Prevents most dysfunctionalities due to software flaws by ensuring all of its functionalities are tested rigorously.

Objectives of functional testing:

Functional testing using mainly black box testing techniques aims to:
  • Strengthen each implementation: Carefully test each implementation, ensuring that it meets the functional requirements of the application.
  • Check key input functions: These tests thoroughly test the entry and exit points of the application, ensuring full coverage.
  • Analyze GUI screen flow: Functional testing carefully analyzes GUI screen flow, ensuring a smooth navigation for users.
Coverage in functional testing
Functional testing includes testing various critical components, e.g.
  • Primary use: Evaluation of ease of navigation of application screens.
  • Main Line Functions: To test the main features and functions of the application.
  • Accessibility: To ensure that all users can access the system.
  • Error status: Viewing the appropriate error messages displayed in error conditions.

Functional Test Workflow:

The functional testing process involves several key steps:
Display of test items: Defines functionality for testing, covers applications, special functions, and error conditions.
Establishing expected outcomes: Developing inputs based on project specifications to define expected outcomes.
Creating test cases: Creating tests as designed and recording results.
Comparison of actual and expected results: Looking at test results to identify barriers and determine program performance.
Functional Test Techniques
Many methods have been used in functional testing, e.g.
  • Unit Testing
  • Integration Testing
  • Smoke Testing
  • User Acceptance Testing
  • Interface Testing
  • Usability Testing
  • System Testing
  • Regression Testing
  • Sanity Testing
  • White Box Testing
  • Black Box Testing
  • Database Testing
  • Adhoc Testing
  • Recovery Testing
  • Static Testing
  • Greybox Testing
  • Component Testing
  • Functional testing and non-functional testing
Functional testing differs from non-functional testing in various aspects, e.g.
  • Parameters Functional Test Nonfunctional Test
  • The definition verifies application usage. Check the behavioral evidence of the application.
  • Test Position: Customers need Customer expectations.
  • Purpose Validate the software actions. Check the functionality of the software system.
  • Requirement Function Description Performance Description.
  • A function describes what the object does. It explains how the product works.

Functional testing tools:

Many tools facilitate functional testing, e.g.
  • Selenium
  • QTP
  • JUnit
  • SoapUI
  • Cucumber
  • Best practices in functional testing

Following best practices increases the effectiveness of functional testing:

  • Automate testing to find bugs faster.
  • Assign tasks to a dedicated automation team.
  • Start building test cases early in the project life cycle.
  • Prioritize automation testing based on importance.
  • Test repeatedly using a defined automation process.
  • Benefits of Functional Testing
  • Functional testing offers several advantages, e.g.
  • To ensure a flawless product.
  • increased customer satisfaction.
  • Attention was paid to the specific issues of consumer use.
  • Validation of application efficiency.
  • Make all products better.

Limitations of functional testing:

Despite the advantages, functional testing has some limitations:
  • The risk of overlooking important errors.
  • the possibility of unnecessary testing.
  • Challenges with unmet needs.
Essentially, functional testing is a cornerstone in software development, ensuring that applications meet performance requirements, and ultimately contributing to the delivery of high-quality and reliable software products.

Functional vs. Non-Functional Testing:

  • Objective:
    • Functional testing confirms the actions that a program performs.
    • Non-functional testing checks performance.
  • Area of Focus:
    • Functional testing focuses more on the various needs that the users will be able to meet when using the product.
    • Non-functional testing evaluates the software based on its performance other than in the conventional criterion like functionality.
  • Ease of Testing:
    • Black box testing is commonly used in functional testing.
    • Graphical user interface: Non-functional testing may involve white box testing.
  • Functionality and Execution:
    • Functional testing identifies what is possible using the product A key goal of functional testing is to provide validation on what is possible using the product.
    • Non-functional testing explains the capabilities of the product.
    • Non-functional testing is comparatively done after functional testing.

Advantages of Functional Testing:

  • Replicates Actual System: Is used to mimic the product in use in a live ambience.
  • Specification-Focused: According to the intention and customer requirements placed on the product.
  • No Assumptions: Runs without a prior knowledge of the structure of the system it is called upon to control.
  • Ensures Quality: Builds and provides customer required bug-free quality product on time.
  • Risk-Based Testing: Eliminates possible dangers that may arise from delays in business, misunderstanding among team members or even conflicts.
As discussed similarly to the Integration testing, the Functional testing is also carried out in the following steps:
  • Determine Functionality: Determine what can or should be tested.
  • Create Input Data: Depending on the specifications of requirements that should be met when acquiring a new item.
  • Determine Expected Output: Specified from the requirement specifications.
  • Execute Test Cases: Verify the real outcomes with the ideal outcomes.
  • Types of Functional Testing
  • Unit Testing: Checks unique statements or instructions of a program.
  • Sanity Testing: It always plays a crucial role of guaranteeing specific vital functionalities are performing efficiently.
  • Smoke Testing: Checks the stability of the structure of the constructed building.
  • Regression Testing: Testing that new code will not interfere with existing functionality so as not to disrupt program performance.
  • Integration Testing: Used to validate end-to-end and test scenarios.
Usability Testing: Checks how users feel and gathers information about satisfaction.

Functional Testing Techniques:

  • Positive Testing:
    • End-User/System Tests: The USE realizations validate the user scenarios.
    • Decision-Based Tests: As a result of systems end results.
    • Alternate Flow Tests: Can ratify other approaches to perform functions.
  • Negative Testing:
    • Equivalence Tests: Divides the test data into partitions.
    • Boundary Value Tests: Thorough testing of data bounds.
    • Ad Hoc Tests: Brings to light facts that went unnoticed elsewhere.
  • Functional Testing Tools:
    • Ranorex Studio: Evaluates graphical user interface for applications with different applications.
    • Selenium: General web app testing tool with python based multi-lingual support.
    • Test IO: Tests functional on live devices and browsers.
    • Telerik: All testing solution services are offered with performance and load testing options.
    • Coded UI Test (CUI Test): Software testing tool which is developed by Microsoft and allows running tests in Visual Studio.

Here's the reference video for you to watch and better understand the topic:

Summary:

Testing comprises the final and essential stage in the development of software applications, where an application’s ability to perform as intended is verified. Thus, software testing is a critical process that plays a profound role in shaping final outputs that meet the expectations of the customers as most bugs that help contribute to the creation of low-quality outputs are removed.
Functional testing, one of the most important subsets of software testing, involves testing of various functions within a software in order to ensure the functions positively relate to the user’s requirement. It is a kind of testing done before the non-functional testing significant for checking the advancements of the software without having extra knowing of its interior form.
Functional testing, conversely, identifies problems and conditions of the system based on the users’ point of view and often employs the white-box testing approach, in addition to aspects of performance, usability, and reliability.
The following are some pros of functional testing: the ability of functional testing to mimic the actual system environment, testing is based on the customer usage specification, and the product meets inherent quality standards and is free from bugs. Thus efficient functional testing serves as an evaluation model in eliminating potential risks that may result in an imperfect product.
Using multiple types of functional testing and appropriate tools like Selenium enhances the speed of the testing procedure and checks the functionality of the software adequately and at a faster rate. They enhance better testing practices that isolate different wider widths and heights, including standard and various probable situations.
To conclude, functional testing is one of the most crucial forms of software testing that helps to identify how well the application works on the surface and what issues users might face during the interaction. Proper approach to testing also plays a crucial role in enhancing the quality of products designed to meet customer needs and expectations.
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