Everything You Need to Know About Functional Testing: A Beginner’s Guide

Software application testing is crucial for the software development life cycle as it defines product quality, efficiency, reliability, performance, and many more aspects. Functional testing is used in the process to verify that an application performs as stated in business requirements. In this blog, we will cover important topics of functional testing, such as what it is, why it is required, what benefits it brings, what challenges come with it, types, strategies, tools, and the future of functional testing, along with the comparison of non-functional testing and how it benefits in agile methodology with choosing the right tools.

What is Functional Testing?

Functional testing is a type of software testing where the basic functionalities of an application are tested against a predetermined set of specifications. Using several functional testing techniques, software testers are checking whether a given input returns the desired output. Result of the functional testing is binary: either Pass or Fail.

📌Example : Imagine there is an E-commerce website where a person wants to purchase an item, checkout the item and do the payment process. Functional testing would require to verify each of these features:

Add to Cart: Does the item get added to the cart successfully?
Checkout: Can the user proceed to checkout smoothly?
Payment: Is the payment processed correctly and verifies if the user can get the payment confirmation.

Scope of Functional Testing

Functional testing covers several areas, including:

The various functions of the software
The look and feel of user interfaces
The way the software talks to databases
How different software parts work together
The steps in business processes
Features that keep the software safe Also functional testing looks at how the application deals with errors and includes testing for regressions. This process helps ensure that new updates or changes don’t mess with features that already work. This fits with the main ideas of quality assurance testing making sure every part of the software gets a thorough test.

To wrap up functional testing is crucial to make sure software is reliable and meets user needs. It’s key to delivering a quality product that works as expected.

Example: Let’s look at an e-commerce app to see functional testing in action. This type of testing checks key features like signing up, finding products, adding stuff to your cart, and buying things. Testers make sure each part does its job right. Say a shopper looks for an item by name – the app should show matching products. Or when someone puts something in their cart and goes to pay, the app needs to get the price right, use any discounts, and handle payments . By giving these features a good workout functional testing ensures the software does what users need and won’t let them down in day-to-day use.

Importance of Functional Testing

Functional testing is important because without this it is not possible to understand whether functions of the application are working accurately. An application may be passed non functional tests and performs well too but, if it is not delivering expected output to the end user, then it can not be considered as working.

🎯Benefits of Functional Testing:

Defect Detection: It identifies functional issues before production.
Requirement Compliance: The software meets all specified requirements.
User Satisfaction: It provides a reliable and predictable user experience, enhancing user satisfaction and trust.
Ensures Functionality: Verifies that the application works according to requirements.
Enhances Quality: The QA process ensures that issues are identified and resolved prior to production, enhancing the overall quality of the final product.
Reduces Risk of Failures: Functional testing helps identify and resolve critical bugs early in the development process. This reduces the risk of software failures and crashes in production, which can be costly and damaging to a company’s reputation.
Enhances Security: Manual testers examine all features, including data processing and storage, to ensure that functionality works appropriately with the protection. If the tester discovers a security risk such as data loss then notify the development team promptly so that it may be resolved. This is how security can be enhanced.
Supports Continuous Integration and Delivery: Automated functional testing is crucial for continuous integration and delivery/deployment(CI/CD) processes. It helps software developers quickly find and fix problems, verifying that new code changes don’t introduce any new issues.
Facilitates Regulatory Compliance: To ensure equality and justice for all, the government established standard rules in many domains, such as healthcare and finance. The tester ensures that the application or website meets all of the criteria to avoid future legal concerns and penalties.
Cost-Effective Over Time: Post-release identified defects are more expensive than those discovered and repaired during development. As a result, testing assists product owners in reducing the cost of rework on products after they have been released, while also improving their market reputation. ## Challenges in Functional Testing Though functional testing has lots of benefits, it also comes with many challenges.

Complexity: As applications become more complex, it gets harder to write detailed test cases that cover all the features.
Integration Issues: Testing integrations with third-party services or different modules of an application can be complicated. These integrations might introduce unexpected bugs that are difficult to trace.
Dynamic Requirements: Functional requirements often change during the development cycle. Keeping test cases up-to-date with evolving requirements demands continuous effort and adaptability.
Automation Difficulties: Automating functional tests can be tough because user interfaces often change, workflows can be complicated, and tests may rely on other systems. Keeping automated test scripts up to date for applications that change frequently takes a lot of time and resources.
Environment Setup: It can be difficult to set up and keep the test environment the same as the production environment. Variations in settings, data, and network conditions can impact the results of the tests.
Data Management: Managing test data for functional testing is crucial. It involves creating, maintaining, and cleaning up test data to ensure accurate and reliable test results.

📌Example : In a healthcare application, the challenges might include:

Complexity: Numerous interdependent features like patient records, appointment scheduling, and billing.
Integration Issues: Managing the integration of multiple third-party medical databases and payment gateways can be challenging.
Dynamic Requirements: Frequent updates to comply with new health regulations and user feedback.

Functional Testing Types

Functional testing can be divided into many types, each focusing on different aspects of the application’s functionality.

Functional-Testing-Types

Integration Testing
Software components are gradually merged and then tested as a whole which is called integration testing. It includes verification of component interfaces and interactions with various system components, including hardware and third-party services.

Conflicts between software modules happen for many reasons, such as incompatibility between subsystem versions, data format conflict, or different processing logic. Integration testing pinpoints those communication issues between software components. It usually occurs after unit testing and before system testing.

Example : In an e-commerce website, tester verifies that the added items cart items quantity and the checkout page items quantity are same.

System Testing
System testing is a sort of software testing that assesses the entire functioning and performance of a comprehensive and fully integrated software system. It determines whether the system fits the given standards and is appropriate for delivery to end users. This type of testing occurs after the integration testing but before the acceptance testing.

Example : Testing the whole e-commerce website shopping process, from searching for a product to placing a purchase order, to confirm that the system functions as it should.

Sanity Testing
Sanity testing is performed on suitable builds. It verifies that the bugs have been fixed in the received build and no further issues are introduced in several specific modules, or the modules impacted by code change. It is a subset of regression testing. It is done after several changes made to the previous build.

Example 1 : In e-commerce application, when receiving a new version of a product with new feature ‘Reset password’, software testers have to ensure that other features like ‘Login’, ‘Forgot Password’, ‘Registration’ are working as expected.

Example 2 : After receiving a new build with bug fix of the login page, verify that the login module is working as expected with the profile module which is the affected module of login.

Smoke Testing
Smoke testing is performed on newly deployed builds to check the critical functionalities are working fine and testers can test the application without any blocker. It can be carried by software testers and software developers both. It is a subset of acceptance testing. It is verified whenever there is a new build, that is why it is known as “build verification testing.”

Example : When a new build is deployed for an e-commerce application, tester or developer tests all the major functionalities such as registration, login, search product, add to cart, checkout, payment process are working as before and there is no blocker that blocks tester to test further.

Regression Testing
Regression testing is a software quality checkup after any changes are made. It involves running tests to make sure that everything still works as it should, even after updates or tweaks to the code. This checks that the software remains reliable and functions properly, maintaining its integrity throughout its development lifecycle.

Example : In an e-commerce application, testers have to test all the functionalities that are implemented and working as expected after getting a build of ‘reset password’ bug fixing to ensure working functionality didn’t break.

User Acceptance Testing (UAT)
User Acceptance Testing (UAT) is the final stage of any software development or change request lifecycle before go-live. UAT means the final stage of any development process to determine that the software does what it was designed to do in real-world situations. Actual users test the software to check whether it is as per business requirements and easy to use. The main purpose of acceptance testing is to validate end-to-end business flow.

Example : Before releasing an e-commerce application to market, real user or client test the whole application functionalities such as registration, login, add to cart, remove cart, place an order with different payment gateways and visuality of application looks good in different devices/browsers to ensure application built as per business requirement and give good user experience.
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