A detailed guide on functional testing that explains various aspects and examples. Keep on reading to know more.
Explaining the Various Aspects of Functional Testing
Functional testing aims at determining if each feature of an application functions in accordance with the specified software requirements. Each function is evaluated against its corresponding requirement to ensure that its output aligns with the expectations of the end user. The testing procedure involves providing sample inputs, capturing resulting outputs, and confirming that the actual outputs match the expected outputs.
Some fine examples of functional testing include:
- Are users capable of logging in to the application successfully when they have the credentials?
- In case a user enters an invalid credit card number, does the payment gateway reject the input and display an error message
- Do inputs on the “Add New Record” screen effectively create and save a new record in the database?
Functional Testing Vs Non-functional Testing
Functional testing differs from non-functional testing as it does not focus on examining the quality, security, or performance of the application’s source code. It doesn’t try to measure speed, scalability, and reliability. Functional testing aims to assess the outcomes of processing rather than the technical details of the process. It evaluates whether the application meets the fundamental user requirements. In this context, the concept of functional testing is closely related to black-box testing, while white-box testing is typically associated with non-functional testing.
Functional Testing vs. Non-Functional Testing
Purpose
Functional testing ensures that an application performs its intended operations and actions. While non-functional testing assesses the behavior and quality attributes of the application.
Testing Basis
Functional testing is based on the customer’s specified requirements. However, non-functional testing aligns with the customer’s expectations for the system’s behavior and performance.
Objective
Functional testing aims to validate the accuracy of software actions, while non-functional testing focuses on evaluating the system’s overall performance.
Requirements
Functional testing relies on functional specifications, while non-functional testing is guided by performance specifications.
Functionality
Functional testing addresses “what” the product does, whereas non-functional testing examines “how” the product works.
Examples of functional testing
Unit testing, integration testing, sanity testing, smoke testing, regression testing.
Examples of Non-Functional Testing
Performance testing, load testing, stress testing, volume testing, usability testing.
Steps of Functional Testing
A functional testing plan has the following sequence:
Identifying testing goals
Functional testing goals are the features that the software is expected to have according to the project requirements. Testing goals include ensuring that the application functions as intended, while also effectively managing errors and unexpected situations.
Develop test scenarios
This process involves creating a list of possible test scenarios for any given feature. These scenarios have the ways that describe how these features will be used. For example- payment module’s test scenarios can have the testing of multiple currencies handling invalid card numbers, and creating a notification successfully when a transaction is done.
Creating test data
Generate test data that mimics typical usage conditions, following the test scenarios you have identified. You have the option to input test data manually. For instance, Data can be input manually (from an MS-Excel spreadsheet or a printout) or automatically through a script or test tool that extracts data from a database, flat file, XML, or spreadsheet. Each set of input data should also come with associated data that defines the expected result that the input data is supposed to produce.
Design test cases
This includes designing test cases that are based on design outcomes for any test input. For instance, in case, an invalid card number is entered, there should be an error message with meaningful note.
Execute the test case
Now it comes to running the test case through the application in order to compare the outcome with what has been expected. If both results are different, the features are considered failed this should be recorded for further reference.
Deliberate on, track and resolve defects
In case a defect is identified, it needs proper recording. There should be a formal tracking system to record the defect. In order to rectify the mistake, the issues should be resolved and aging it should undergo testing to confirm issue resolution.
How do Automated Functional Testing tools work?
Functional test automation tools are capable of interacting with the user interface of the application under test. They have the ability to recognize on-screen elements like list boxes, text boxes, and buttons, enabling them to select items, input information, and interact with these elements.
Numerous functional test automation tools come equipped with a recorder. The recorder observes the user’s interaction with an application and its on-screen elements. It captures the data entered into the system and logs the actions performed by the user – from pressing buttons to selecting menus. These actions can be replayed using the objects, data, and actions recorded. This allows for replicating the user’s activities. The outcomes of these actions are recorded by the testing tool and then juxtaposed against the expected results outlined by the automation engineer to ascertain the success or failure of the test.
Functional test automation engineers have the flexibility to gradually construct their tests by working with the tool’s recognized objects. Alternatively, they can kickstart the process by recording the steps, then tweak them, and parameterize the data for broader applicability. This approach allows the tests to be compatible with different environments, spanning across multiple browsers and mobile devices.
Role of Artificial Intelligence in Functional Tools
Artificial intelligence has become an important part of functional tools today. The advanced AI capabilities including machine learning, computer vision, neural networks, and natural language processing help it perform better. This technology assists in recognizing on-screen elements just like a human does. It also allows for natural interaction and manipulation of objects, and facilitates the creation of tests using simple language.
AI-based functional test automation has demonstrated the ability to shorten the time taken to create tests, enhance test coverage, improve the resilience of testing assets, and minimize the effort needed for test maintenance.
Functional Testing Best Practices
Here is a brief on the best practices used in functional testing.
Early test case creation
Creating test cases earlier is important as it can faster the overall process. Waiting for an application or module to be completed and starting the procedure after that will take considerable time.
Automate
Functional testing may seem to be repetitive and a time-consuming procedure. As you will automate the task, you will have a considerable time for managing other related jobs. It additionally will help to save the save additional cost as well. However, not all test cases should be automated, and therefore you will have to choose carefully which tasks would you like to automate.
Understanding the thought process of users
Having an idea about user’s though process will help to add attributes that users would like to see in the application. Different types of applications will demand different navigation that becomes easy to implement with how users take an application.
Prioritize
Prioritizing tasks will provide a timeline for completing them on time. Moreover, there may be some scenarios when some tasks will be on high-priority than other. Giving your time as per the priority of the task will help to manage it accordingly.
Benefits of Functional Testing
Bug-free result
The result of Functional testing is a bug-free and high-quality product.
Satisfied customers
The outcome of a functional testing ensures that the customer is satisfied as it s provided after confirming all the requirements.
Specification-focused testing:
Functional testing focuses on specifications as per customer usage.
Top-notch app functioning:
After the functional test is done, the app offers top-notch functioning ensuring that it functions well.
Improved quality
As functional testing is all about testing all the attributes of apps and software, it ensures improved product quality.
Limitations of Functional Testing
Missing critical errors:
There are events when executing functional testing may critically miss logical errors.
Redundant testing
Performing redundant testing may be a case for some testers.
Requirements that are not complete
Performing test cases becomes difficult when the requirement is not complete.
Functional Testing Tools
Here is a brief on tools popular for functional testing
Selenium
The tool is an open-source umbrella project. It is ideal to use for a wide range of tools and libraries developed for supporting browser automation. Selenium is also the right choice of tool for automating web browser. Additionally, the tool has single interface, which is helpful for writers in developing test scripts in languages like Ruby, Java, NodeJS, etc.
Cucumber
Cucumber is another open-source testing tool backed by Ruby language. The tool finds its usage in emphasising on end-user experience with an easy execution and setup process.
JUnit
As an open-source framework for the Java programming language, JUint is developer’s tool for writing executing automated test cases. Along with Selenium WebDriver, the tool is good to use. It further helps to automate tests for web applications.
QTP
QTP abbreviated as Quick Test Professional is an automated functional testing tool. The tool identifies its use in web and desktop application testing. QTP is among the most popular and widely used automation tools.
SoapUI
SoapUI is one of the most popular tools for testing rapid functional and load testing. The graphic interface is an easy-to-use offering for users. Additionally, it offers a free code test environment.
Conclusion
Functional testing is an important aspect of software application testing. It is an easy-to-use way for focusing on user-interface and functionality. Functional testing seems an effective offering. However, there may be some shortcoming of it as it may involve repetitive testing. Therefore, the testing requires the right approach for delivering bug-free products ensuring its optimal quality as well.
FAQ
What is functional testing in software development?
Functional testing in software development is all about evaluating an app’s core functionality. It is a method to ensure the work is being done keeping user’s requirement in mind.
How often should functional tests be run?
Functional testing runs continually during the development phase. It is important to perform before major app releases and at every stage of issue fixing.
Is UI testing functional testing?
Yes, UI testing falls under the category of functional testing.
Is it possible to automate functional testing entirely?
Certain aspects of functional testing are easy to automat. This includes repetitive tasks as well as regression tests. For other important test cases, manual testing suits the best.
