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Introduction
Welcome, Ninjas! Before we launch any product in the market, it is necessary to test it. It ensures that the product released is up to the mark. Various types of testing can be done to test the frameworks and software.
This article,' What is Functional Testing? Types & Examples ', will discuss the meaning of functional testing and its types and implementation.
Let us get started!
What is Functional testing?
Software Testing can be performed in two ways, Functional and Non-functional. Functional testing verifies and ensures that a system or component has the required functionality. It includes the formation of test cases and evaluating them. Testing can be performed with the help of frameworks such as JUnit, JTest, pytest, etc. Functional testing also tests the compatibility of the product or the system. In short, it verifies that the product works according to the requirements.
Functional vs Non-functional testing
Functional and non-functional testing is important to make sure that the quality and performance of a software application are maintained. Below are some of the major differences between functional and non-functional testing.
Basis
Functional
Non-functional
Purpose
Functional testing is used for verifying the functions, operations, and actions of the software.
Non-functional testing verifies the behavior of a software application. It verifies the non-functional attributes.
Requirement
Functional requirements are easy to define.
Non-Functional requirements are difficult to define.
Focus
Functional testing is based on the requirements of a customer.
Non-functional testing is based on the expectation of customers.
Testing techniques
Functional testing uses the black-box technique.
Non-functional testing uses techniques on the basis of certain attributes that are being tested.
Objective
Functional testing is done to validate software actions.
Functional testing tells us what the application does.
Non-functional testing describes the working of the application.
Manual Testing
Manual testing is easy to perform in functional testing.
Manual testing is challenging to perform in non-functional testing.
Examples
Unit testing, smoke testing, regression testing, localization, globalization, user acceptance, etc.,
Performance testing, volume testing, load testing, stress testing, disaster recovery testing, and scalability. etc.
Functional Testing Types
The lowest level of testing is Unit Testing. In Unit Testing, we test the individual units. The highest level of testing is Acceptance testing. In Acceptance Testing, the end user verifies if the product meets the requirements.
Unit Testing
Unit testing considers a system as a collection of units. We test various software units during unit testing, ensuring the whole system is tested. It tests if the individual units of code are working properly.
How to perform Unit Testing:
Unit testing can be performed manually as well as can be automated. But it’s better to perform automated Unit Testing. It can be performed with the help of frameworks such as JUnit for java, pytest for testing python codes, etc.
Examples:
Examples of unit testing include:
Testing an input by the user according to his requirements.
Testing a mathematical function if it gives the correct output.
Testing database queries if they return the correct output.
Testing a class.
Integration Testing
The next testing after unit testing is Integration Testing. It forms the second level in software testing. After testing the individual units, the units are tested in combinations.
In general terms, Integration means combining or integrating two or more things. Similarly, integration testing tests how different components of software interact or communicate.
What's the one thing you need to live in a society? It is Peace. If there's no peace, human society cannot function. In the same way, Integration testing checks if the components are working together in peace, without any conflicts. It also detects any defects existing between the two components. Testing between the interfaces of different components or units is done.
How to perform Integration Testing:
There are various approaches to Integration testing.
Big Bang Approach: In this, we do not go for individual testing of units. We consider the system as a whole, an integrated unit. Then, test if it works and meets the requirements.
Bottom-Up Approach: It starts by testing the innermost components of the system. Then, it moves to the complex components by integrating modules at each step.
Top-Down Approach: This approach starts from the topmost component or the module. Then we move to the lower modules by integrating them and testing them. Note that the topmost module is tested alone.
Examples:
Examples of integration testing include:
Testing the integration between an e-commerce application and its payment gateway.
Testing the integration between an application and its database.
Interface Testing
After Integration testing, the next is Interface testing.
As the name suggests, Interface testing tests the interfaces between different components or modules of the software. It ensures that the interfaces between the two modules work as intended and can share information. Error handling is also a feature of Interface testing.
How to perform Interface Testing:
In interface testing, two main interfaces are tested. One interface is between the application & the database. The other interface is between the web server and the application.
Firstly, we identify the two components whose interface will be tested.
Then, we configure the interface and verify it.
After that, the interface is validated if it's showing errors.
Then, after the testing of the interface, it’s monitored to perform fine.
Examples:
Examples of interface testing include:
Testing the database and the application.
Testing the front-end and the back-end of the application.
System Testing
Now, we have tested the units, the communication between the units, and the communication unit, i.e., the interface.
It is now time to test the system's functionality as a whole. This is where the System Testing comes in. It verifies the complete and integrated smooth functioning of the system. It ensures the system works as intended (according to the requirements). After this testing, almost all the errors are found and resolved.
How to perform System Testing:
System testing is performed after integration testing. It doesn't require internal knowledge of software code; thus, it is a black-box testing technique.
System Testing can be done by following some steps.
Developing a test plan: Configure the objectives of testing the system and form the test cases to be executed.
Setting up the test environment: Configure the hardware and software modules required for testing.
Executing the test cases: The test cases developed during the test plan are executed, and errors and defects, if any, are detected.
Evaluate the test results: After executing the test cases, analyze the test outputs or results and check if they are as expected.
Report the defects: If any defects or errors are detected, Report them and document the steps taken to reproduce the issue.
Regression Testing: The software is retested after the errors are resolved.
Examples:
Examples of system testing include:
Testing the system’s security features.
Testing the system’s ability to recover from failures.
Ensuring that all components work together without conflicts.
Regression Testing
Let's say we detected some faults while testing and made changes to resolve them. The modifications are applied to the code or any function of a module or component of the software to resolve the errors. After that, we perform Regression testing. It verifies that the modification in code does not affect the software's existing functionality.
We can perform regression testing in the following ways.
Corrective Regression Testing: It is the simplest form of Regression testing. It ensures that the fixed errors do not lead to new errors in the software.
Unit Regression Testing: Individual unit is tested, and the others are disabled.
Selective Regression Testing: Only Selective test cases are re-executed. This is done after the changes are made.
Progressive Regression Testing: In Progressive Regression Testing, we add new test cases while re-executing the previous ones after the changes are made.
Complete Regression Testing: In complete regression testing, all test cases are re-executed after changes are made to the system. It is done regardless of whether or not the changes are related to the test cases.
Retest-all Regression Testing: Re-test all Regression testing, as the name suggests, re-tests all the test cases by executing them again to verify that no errors exist.
Examples:
Examples of Regression testing include:
Testing software against new test cases ensures the existing functionality.
Testing the user experience.
Smoke Testing
Smoke Testing forms a subset of Acceptance testing. Every software has some critical functionalities or modules without which the software might fail. Smoke testing verifies the stability of those critical functionalities. It ensures the stability of the system.
How to perform Smoke Testing:
Smoke Testing can be done both manually and can be automated. Automated testing is preferred. Firstly, we identify the critical module which has to be tested. Various test case scenarios are listed, and test case results are evaluated.
Examples:
Examples of Smoke testing include:
Testing the installation of software.
Testing the software’s stability.
Sanity Testing
Sanity testing forms a subset of regression testing.
Let's say we detected some faults while testing. We made changes to resolve them. We make modifications to the code of a module of the software to resolve the errors. Sanity testing is performed to verify if the errors are resolved. It also ensures that resolving one doesn't lead to new errors.
How to perform Sanity Testing:
Sanity testing is similar to Smoke Testing. Firstly, we identify the module to be tested. Various test case scenarios are listed, and test case results are evaluated.
Examples:
Examples of Sanity testing include:
Testing the user-friendliness of a product.
Testing and validating the data input.
Testing the performance and responsiveness of a product
Acceptance Testing
After all the testing is done, we perform the final testing of the software, i.e., Acceptance Testing. This is done before deploying the software. As the name suggests, acceptance testing ensures that the end user accepts the software. The client ensures that the software meets all his requirements in this testing.
How to perform Acceptance Testing:
Various methods to perform Acceptance Testing is described as follows.
User Acceptance Testing: The end user tests the product to see if it works just as intended.
Business Acceptance Testing: It ensures that the product meets the business goals and benefits.
Contract Acceptance Testing (CAT): It ensures that the product fully satisfies all acceptance test cases after going live.
Regulations/Compliance Acceptance Testing (RAT): This testing is performed to ensure that the product doesn't violate the rules and regulations. The country's government defines rules and regulations.
Operational Acceptance Testing (OAT): In this type of testing, operational readiness, like recovery, availability, etc., of the product is ensured.
Alpha Testing: Alpha Testing ensures that a team of alpha testers tests the product.
Beta Testing/Field Testing: In this testing, the product is exposed to the actual end-users, called beta testers. Feedback is collected from them. It enhances the user experience.
Examples:
Examples of Acceptance testing:
Adding new features by alpha testers to any application. Beta users do testing of those.
Ensuring the application doesn’t fail when introduced in the real world.
How to do Functional Testing?
Functional testing aims to verify that the requirements of the application are met and that it functions according to the plan.
Let's take an example, assume there is an e-commerce website, so its functional testing will involve testing of functions such as product search, user integrations, checkout processes, etc.
The testers perform the intended actions that a user would perform while using the application, and then the comparison is made between the expected and actual results. If there is any defect, it is reported and fixed; again, retesting is done to ensure it works properly.
The steps performed in function testing are mentioned below.
Creating input values
In this step, we first determine what functionality of the application is to be tested. Therefore, input data is created for the particular functionality. Certain parameters are defined for acceptable outputs.
Executing test case
Next, The designed test cases are executed. The test cases are designed in such a way that they cover different functionalities and circumstances.
Comparison of actual and expected results
This step tells if the system is working up to expectations by comparing the actual results to the anticipated results.
What is the difference between functional and non-functional testing?
Functional testing verifies the functionality of a system. Non-functional tests the non-functional aspects of a system, such as performance & security.
Give an example of the software used for automated testing.
Katalon Studio can be used.
Why is automated testing better?
Automated testing is better than manual testing because it’s reliable and fast.
What are the 4 levels of functional testing?
Unit testing, Integration testing, System testing, and Acceptance testing are the four levels of testing. The main aim of unit testing is to test individual code units; the verification of the interaction between various units is done by integration testing. While system testing evaluates the functionality of the system, and acceptance testing makes sure that the system requirements are fulfilled.
What is QA functional testing?
Software testing, whose main aim is to verify if a system’s application functions work as planned and meet the requirements, and tests the overall behavior of a system, is QA functional testing. The testing of the functionality and integration of individual components is done in QA functional testing.
Conclusion
In the article,' What is Functional Testing? Types & Examples ', we discussed the meaning of functional testing and its types and implementation.
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