Explore various software testing types in this concise guide. From unit testing to acceptance testing, learn their purposes, processes, and best practices. Gain practical insights to enhance your testing skills and ensure software quality. Perfect for both newcomers and seasoned QA professionals.

1. SOFTWARE
TESTING TYPES
Every QA Needs to Know

2. Unit Testing
Integration Testing
System Testing
Acceptance Testing
Definitions
Security Testing
Performance Testing
Usability testing
Compatibility Testing
Conclusion
TABLE OF
CONTENTS
FUNCTIONAL TESTING
NON-FUNCTIONAL TESTING
1
2

3. Software testing is a crucial part of the SDLC (Software development life
cycle) to ensure that the software program is error-free. Testers need to
perform various types of software testing to ensure that all the components
of the software are working.
The following graphic will give you a good idea of the classification of
software testing in the hierarchy.
In this book , we have talked about the different types of software testing,
their working methodologies, and practical examples of each.
Functional Testing
Functional Testing is performed to test if the software works as intended
and meets the expectations of end-users by providing accurate results. It
evaluates the functionality of software by testing its features and
capabilities against specified requirements.
Here, testers prepare various test cases to simulate user interactions, as
well as prepare datasets and test software’s functionality for these
interactions.
Benefits of Functional Testing:
It ensures that software meets the specific user requirements and meets
the end-user’s needs.
Testers can address the missing features and identify the gap between
the software’s intended behavior and actual implementation.
By validating the features that meet regulatory compliance and
guidelines, testers can mitigate compliance risks at an early stage.
Examples:
The examples include anything that performs the working of an application
or its certain feature. For instance, functional testing for the “Add to Cart”
button in eCommerce websites.
Or, say, testing the “Search” feature in the music streaming application.

4. 1) Unit Testing
Unit Testing is a crucial part of functional testing. It tests for the individual unit or a
particular feature of the software system. Unit tests are automated and are
performed in isolation to test each feature individually.
Testers can perform unit testing by writing various test cases to test these codes.
This way, they can catch and detect the bugs at an application development stage.
Benefits of unit testing:
Detects bugs and issues at an early stage to save time and money before issues
become larger.
Performing tests in isolation ensures that the changes in code do not introduce
new bugs.
Exposes the edge cases and helps you write refactored and optimized codes.
Example:
An application can be logged in using a password that contains eight characters and a
symbol. Developers can perform the unit test on these text fields by entering a
password with less than eight characters or no symbols.
White Box Testing
1.
White box testing is a technique for evaluating the internal structure of a software
system. It tests the internal codes, product architecture, internal design, and code
structure to determine the software’s internal performance and efficiency.
Also called open box testing or transparent box testing, this type of testing is useful
for detecting loopholes in the design of the application. The tester has access to the
source code and documentation, using which it designs the test cases to test software
at the code level.
Example:
Consider an example of an online portal that requires the sign-up and log in.
With access to the source code, the testers will perform tests on code responsible for
the authorization. This involves inspecting the source codes to test the scenarios like
valid user credentials, incorrect passwords, and failed login attempts.

5. Gorilla Testing
1.
Gorilla testing is a software testing technique that performs a single feature or
functionality for errors. The test uses the minimum number of test cases to
evaluate the software through all aspects.
Its purpose is to find as many errors as possible in a short period of time. Hence,
it is the best testing technique for the testers when the time is limited. Here, the
test cases are chosen at random and the tests are performed consistently to
make sure the detected errors are not by chance.
It increases test coverage since it tests multiple aspects in a single test.
Example:
Consider a financial institution rolling out a new online banking system. Testers
might randomly navigate through different banking services, such as account
balance inquiries, fund transfers, bill payments, or loan applications.
They can test each module of these online banking services for positive and
negative scenarios.
2) Integration Testing
Integration testing is a technique for evaluating the functioning of software when
two units are combined. The purpose of the test is to determine whether the two
features work efficiently for the end users.
Integration testing is performed after the unit testing to verify that the interface
connection works seamlessly and meets the specific requirements. It tests for
critical faults such as incorrect data transfer, messy interface, or improper
functioning when two features combine.
Integration testing can be performed in three ways: top-down testing, bottom-up,
and big-bang testing.
Benefits of Integration testing:
Makes debugging and error detection easier since faults can be isolated to
specific interfaces.
Validates the data flow between different systems and processes to ensure
data integrity.
Provides additional reliability and stability to software functioning.

6. A user adds products to the shopping cart and proceeds with the payment.
Here, testers need to perform integration testing for different modules.
Integrating testing should be done to check for the working of the product
catalog and checkout cart together and the working of the checkout cart and
payment processor together.
Grey box testing
1.
Grey box testing is a technique that combines the elements of white box
testing and black box testing. The tester has limited knowledge of the
documentation and internal working of the system.
Grey box testing is performed in cases where third-party components or legacy
systems are involved.
The purpose of grey box testing is to identify defects by leveraging the
internal and external environments. This way, testers can also prepare the test
cases that are specified for some areas or software features that might have
issues. It also ensures that performance is evaluated from the external user
perspective.
The best part; it does not require high-programming knowledge since it
involves the best of black and white box testing.
Example:
A software company developing a web application integrates with a third-party
payment processing service to handle online transactions. The development
team has access to the API documentation provided by the payment processor,
which outlines how the integration should work, but they don’t have visibility
into the actual implementation details of the payment service’s code.
In this case, the testers can perform grey box testing to ensure that the
integration between the web application and the payment processing service
functions correctly.

7. 3) System Testing
System testing is performed to test the overall functionality of the software and
the performance of a completely integrated system. This test is performed after
the integration testing and before the acceptance testing.
The purpose of system testing is to check if the system meets the specific
requirements and hence, is done from the end-user’s perspective.
Benefits of System testing:
Efficiently identifies the errors and bugs that may not be detected during
the unit testing and integration testing.
Checks for system requirements and ensures it offers compliance with
regulatory bodies.
Replicates the real-time production or business environment.
Example:
Take an example of an airline reservation system that involves actions like
searching a flight, entering the passenger details, making payment and
confirming the payment. The system integrates with various components such
as flight databases, payment gateways, and user authentication systems.
Testers will perform various testing types like functional testing, unit and
integration tests individually for these components. System testing will test for
tasks like maintaining real-time flight databases, faster processing and secured
payments.
End-to-end testing
1.
This software testing type is the most comprehensive one since it involves
testing the entire sequence of actions from user input to the final output. The
purpose of this testing is to mimic the real-world use of the software as a
whole rather than individually testing a unit or module.
End-to-end testing is performed to identify any potential issues or defects in
the application, such as integration problems, data loss, security vulnerabilities,
and user experience issue

8. Example:
Let’s say a tester needs to perform all the functionalities of an online insurance
site. It tests for the insurer’s details, policy page, calculation of policy, payment
processor, connection with third-party, and confirmation receipt.
Black box testing
1.
Opposite to white box testing, testers do not have access to any internal source
codes or processes in Black box testing. Here, testers perform tests based on the
provided specifications or requirements without knowing the process of
implementation.
All in all, black box testing only focuses on the input and output of the test
objects.
Example:
Imagine testing the features of a payment gateway. Without delving into the
internal mechanism, testers perform tests on the messages displayed in case of
wrong credentials or a successful payment message.
Smoke testing
1.
Smoke testing is performed to evaluate the basic and critical functionality of the
system. It is also performed to validate that the system under test is ready for
further testing.
It is performed at an early stage of the development cycle or when a new build
is deployed. The testing team validates the functionalities of this new build to
ensure that it is stable.
Example:
Assume that there is a music streaming app with over 20 modules. However, the
four main components are one-click login, adding and removing the songs, pause
and play. Smoke testing doesn’t perform the edge cases but looks into the
crucial testing.
Instead of checking the process, it checks if the one-click login works well.

9. 4) Acceptance Testing
Acceptance testing is the last testing stage before the product release. This
testing technique tests all the functionalities and performance of the software/
application from the end user’s perspective.
The purpose of acceptance testing is to ensure that the application meets the
business and user’s specific requirements. UAT analyses the stakeholder’s and
user’s behavior by executing the pre-defined test cases and evaluating the
behavior in a real-world environment.
Benefits of Acceptance testing:
Clients are directly involved in the testing process, making a final product as
intended.
Provides effective communication between developers and end-users.
Tests are performed for multiple browsers, operating systems and test
environments
Alpha testing
1.
Alpha testing is a part of the acceptance testing which is performed by the
project team to find as many defects as possible before releasing software to the
customers.
The purpose of this test is to identify the bugs, evaluate each feature and garner
user’s feedback.
Example:
An eCommerce site under alpha testing will perform the functionalities like
searching products through search bar, using the categories, sorting the product
catalogs, adding product to carts and checking for the integration of payment
gateway with checkout cart and more.
All of these real world scenarios will be performed by the QA testers or internal
team.
Beta testing
1.
Beta testing is the first stage when the product is released for the real users.
Here, the software is released to the large pool of beta users that test the
functionality of software to give their critical feedback.

10. It is considered successful when the customer accepts the software.
Example:
A restaurant chain releases the scan and pay service for the customers.
Before announcing it to the public, the company releases it for the loyal
customers and gathers their feedback in return for rewards and discounts.
OAT
1.
Operational acceptance testing checks for the operational efficiency of the
app and its usability in the real world. This test is performed by the
operations team or a system administrator for evaluating factors such as
performance, reliability, security, and scalability when deployed.
OAT focuses on the following points:
Testing of requirements
Testing the codes
Installing and Uninstalling apps
User management and
Maintenance of software
Example:
A large e-commerce company is preparing to launch a new version of its
online shopping platform. The platform has undergone thorough functional
testing, user acceptance testing, and performance testing. Now, the
company needs to ensure that the platform is operationally ready for
deployment in its production environment.
The operational team writes test cases to perform tests for performance,
reliability, security and access control, and backup & recovery.

11. Non-functional testing is a testing technique that tests for the non-functional
aspects of the software/ application. It does not perform tests from the user’s
perspective but digs deeper into the internal workings of the system.
Non-functional testing is equally important as functional testing, as it examines
the system’s performance, efficiency, security, and compatibility.
Benefits of Non-functional testing:
Helps identify the bottlenecks and factors that impact the performance.
Checks on improving the overall user experience and interface friendliness
Evaluates the app according to the higher volume of traffic.
Example:
A tester can perform a test to see how the software reacts to an unauthorized
action in the system. Similarly, it runs tests to see if the app will slow down,
crash or run smoothly when unexpected traffic increases.
1) Security Testing
Security testing is done to check the system vulnerability in case of external or
internal security threats. This testing helps you establish a strong security
system for your website/app and identify the potential threats, malicious
programs or viruses that affect it.
It also runs tests to check for secured data management, user management and
data recovery.
Benefits of Security testing:
Helps identify potential threats and security vulnerabilities
Tests for various security standards and regulations such as HIPAA, PCI DSS,
and SOC2.
Saves time and cost in the early stage of software development and avoids
embarrassing security incidents.
Non-Functional Testing

12. Example:
Take an example of an online financial institution that is launching a banking
website. A tester performs security testing to check for unauthorized access,
manage password keys, secure communication, and protect data.
This way, the financial institution can identify and mitigate potential security
risks, safeguard customer data, and maintain trust in its online banking
application.
Penetration testing
1.
Penetration testing or ‘Pen testing’ is a testing technique to simulate real-world
cyberattacks on the system and identify the weak points and vulnerabilities in
the system.
The test is performed by ethical hackers who perform actions to breach the
security systems to identify the vulnerabilities.
The ethical testers perform various operations such as SQL injection, URL
manipulation, session expiry and provide reports to the organization.
2) Performance Testing
Performance testing tests a software/application’s responsiveness, speed,
scalability, and stability under normal or peak load conditions. The purpose of
this testing is to identify performance bottlenecks, resource utilization issues,
and scalability limitations to ensure a seamless user experience.
The tests are performed in accordance with the industry standards and
benchmarks.
Benefits of Performance Testing:
Identify the resource utilization of elements like CPU, RAM and bandwidth
during a traffic spike
Reduces the risk of crashes, downtime and revenue loss
Tests for the user experience and customer satisfaction through various
test types.

13. Example:
An eCommerce website is planning for a major discount program that is likely to
garner a significant spike in user activity. A tester needs to perform a performance
test for a sudden traffic spike, response time, CPU utilization and memory usage.
Performance test helps developers create a system that ensures delivering a fast,
responsive, and reliable user experience to its millions of users.
Load testing
1.
Load testing determines the system behavior when multiple users use it at the same
time. It simulates the real-world load to check its performance under stress. The
purpose of this testing is to identify the bottlenecks and see how it will perform
under a specific number of users.
Hence, load testing mitigates the risk associated with heavy traffic loads and slow
response times.
Example:
An application system can withstand a maximum of 100 users at a time with a
response time of 5 seconds. Testers run load testing to test with a maximum of 100
or less than 100 users. The purpose of the test is to see whether it loads under 5
seconds.
Stress testing
1.
Stress testing tests for the system behavior and responsiveness by applying load or,
say, more users than intended. The main purpose of stress testing is to test
systems under exceptional user loads, excessive data volumes, or limited system
resources.
It checks for the system’s breaking points, app crashes and performance
degradation.
Example:
An application system can withstand a maximum of 1,000 users at a time with a
response time of 5 seconds. Testers run load testing to test with 1100, 1200, 1300
or more users. The purpose of the test is to see whether it breaks down, responds
slowly or performs optimally.

14. Spike testing
1.
Spike testing is another performance testing technique to assess how a system
will perform with a sudden spike in traffic. This test checks whether the system
will function correctly when change is made in size or volume of the system and
resources and scaled up and down.
The test is performed to manage the scheduled increase in user traffic, data
volume, transaction counts frequency, and more.
Example:
Let’s say, a travel site handles a maximum of 1000 users with a response time of
3 seconds. Testers perform spike testing by increasing the number of users to
more than 1,000 users and then gradually increasing the number of users to
determine the breaking point or crash.
Suppose a website may withstand a load of up to 3,000 users and may crash
after the 3,100 users threshold.
Volume testing
1.
Volume testing tests for the system performance when the software/application
is subjected to a high volume of data. Also called the floor testing, it works by
sending a large volume of data in the database.
This testing is done to check for the system responsiveness and loading times in
case of large volume data.
Example:
Let’s say, a banking mobile app stores X GB of data for storing customer data
and other documents. In the next 2 years, the app will have to store 5*X GB of
data and in the next 5 years, the app will have 10* X GB of data to store.

15. 3) Usability testing:
Usability testing is performed to test the UI and determine how easy the
application/software is to use from the end-user’s perspective. The purpose of
this test is to check the system’s usability in terms of navigation controls, menu
bar, footer, and visual design.
Testers need to thoroughly work the system internally and externally since it is
performed extensively.
Benefits of Usability testing:
Performs tests from the end-user’s perspective
Gives a major competitive advantage over others in improving usability
Check how long it will take to complete a specific task
Example:
Let’s say, a pet eCommerce app has various navigational options and users have
to perform usability testing. Testers run the test cases to see if the app can be
operated with one hand, reacts to gestures, check usability in horizontal and
vertical view and and text overlay with footer and menu.
Exploratory testing
1.
As the name says, this type of software testing is performed to explore the
software/applications and identify the defects on the go. This is an unscripted
approach where there are no predefined test cases.
Instead, the test cases are written on the fly as the testers explore the apps. All in
all, exploratory testing checks for the functionality, operations and all the
technical faults in the system.
Example: Let’s say, an online banking app has undergone structure testing,
integrated and system testing by following predefined test cases. Testers can
perform exploratory testing to uncover potential usability issues, edge cases, or
unexpected behavior.
The apps can be run for various browsers, real-time interactions, test boundaries
and check for security measures.

16. Accessibility testing
Accessibility testing tests whether the application or system is accessible to
disabled people. By disabled, we mean people suffering from vision impairment,
hearing disabilities, and physical or cognitive conditions like color blindness, old
age, and others.
Testers need to perform various tests such as font size for the visually impaired,
color checks for color blindness, and audio tests for deaf persons.
Example:
A simple example of how a tester or an SEO would check the alt texts of images
in a website or the app. The alt texts in the images can aid individuals who rely on
screen readers.
Testers can run tests and review each image element in the website’s code to
ensure that it includes descriptive alt text that conveys the meaning or function
of the image accurately.
For instance, a “buy now” button should have an alt text as buy now and not
image.1 to ensure it is readable for the visually impaired.
4) Compatibility Testing
Compatibility testing is done to test the application performance and how it runs
in different environments, web servers, hardware, and network environments. This
testing checks for the compatibility of software on different network servers,
configurations and respective versions.
Benefits of Compatibility testing:
Helps detect the bugs during the development stage
Prepares the software for various network configurations and versions.
Example:
A mobile app that is designed for both Android and iOS has to be tested for
various network configurations, Android versions and iOS versions. Testers should
perform tests across multiple screen sizes and hardware configurations.
Compatibility testing checks for inconsistencies, bugs, or issues that may arise on
specific devices or operating system versions.

17. Cross-browser testing
1.
This testing type tests a software/application on various real browsers like
Chrome, Safari, Edge and others. The purpose of this test is to offer a good user
experience on different browser types.
Example:
A tester wants to check for the usability and functionality of an insurance website
or application in different browsers and check the load speed and usability in
each.
Cross-platform testing
1.
Cross-platform testing is a type of testing that tests software/applications on
various platforms or operating systems to test for its functionality, scalability and
behavior. Testers perform this software testing on platforms like Windows, MacOS,
Linux, iOS, Android, or any other platform.
Example:
Imagine a website or on-premise software designed to work on all operating
systems. A tester would perform tests on its usability, functionality, and
compatibility when run on different operating systems, such as Windows, MacOS,
Linux, and others.

18. In conclusion, software testing plays a crucial role in ensuring the quality, reliability,
and functionality of software applications throughout the software development life
cycle (SDLC). Through various testing techniques and methodologies, testers can
identify and address defects, vulnerabilities, and performance issues, ultimately
enhancing the user experience and minimizing risks associated with software
deployment.
Functional testing, including unit testing, white box testing, and gorilla testing,
focuses on evaluating the software's features, functionality, and internal structure.
Integration testing ensures the seamless interaction between different components
or units of the software, while system testing evaluates the overall functionality and
performance of the integrated system.
Acceptance testing, including alpha and beta testing, involves assessing the
software's readiness for release from the end user's perspective, ensuring it meets
business requirements and user expectations. Operational acceptance testing (OAT)
examines the operational efficiency and usability of the software in real-world
environments.
Non-functional testing, such as security testing and performance testing, evaluates
aspects like security vulnerabilities, system responsiveness, scalability, and
reliability. Usability testing focuses on assessing the user interface and user
experience, ensuring ease of use and navigation.
Exploratory testing allows testers to uncover defects and unexpected behavior in
real-time, while accessibility testing ensures that the software is accessible to users
with disabilities. Compatibility testing ensures the software's compatibility across
different environments, platforms, and devices, including cross-browser and cross-
platform compatibility.
In essence, by implementing a comprehensive testing strategy that encompasses
various testing techniques and methodologies, organizations can ensure the delivery
of high-quality software that meets user expectations, complies with industry
standards, and withstands the challenges of the ever-evolving technological
landscape.

19. References :
https://artoftesting.com/
https://testgrid.io/blog/types-of-software-testing