Software testing is an essential element of the Software Development Life Cycle (SDLC) that ensures the quality, reliability, and functionality of software applications. And with software testing engineers earning salaries in excess of $95k, there’s no denying that it’s a valuable skill to have.
All the same, if you’re asking the question, what are the different types of software testing, we’ve got you covered. In this article, we’ll dive into the different types of software testing you need to know in 2024, including definitions and usage.
The Core Principles of Software Testing
- Testing is context-dependent: Different applications have different requirements and constraints, so your test should be tailored to the context.
- Absence of errors fallacy: The absence of errors does not guarantee the absence of defects in a software application. Software testing should be designed to cover identified and potential bugs.
- Early testing: This helps detect errors early, reducing the cost and effort required to fix them later.
- Pesticide paradox: Repeating the same tests multiple times can result in finding the same errors while missing new issues. Tests should be revised regularly to include new cases.
- Defect clustering: A small number of modules in a software application are often responsible for the majority of defects, so testing should focus on identifying and testing these thoroughly.
- Exhaustive tests are impossible: Due to the often limitless number of test scenarios, testing every combination of inputs and conditions is impossible.
Manual vs Automated Testing
When it comes to software testing and types of testing, the most fundamental distinction is between manual and automated testing.
Manual testing: Human testers execute tests on a software application to identify errors. The tester follows a predetermined set of test cases to ensure the application performs as expected. This is a labor-intensive process and can be slow.
Automated testing: Uses software testing tools to execute tests on software applications. With this, tests are pre-programmed, allowing automated testing tools to compare actual results with expected results.
Generally speaking, automated testing is faster, more efficient, and more reliable than manual testing, but it requires expertise in the programming language and software tools used.
Let’s look at some more differences between manual and automated testing.
|
|
Manual Testing |
Automated Testing |
|
Definition |
Software testing that’s conducted manually by human testers |
Software testing conducted using specialized tools/scripts |
|
When to use |
For exploratory and ad-hoc testing, usability testing, etc |
For regression testing, load testing, performance testing, etc |
|
Required Resources |
Human testers, test cases, test data |
Automated testing tools, test scripts, test data |
|
Generating reports |
Reports may be generated manually |
Reports may be generated automatically |
|
Programming knowledge |
May be required |
Required to write test scripts and use testing tools. |
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The Different Types Of Software Testing
Software testing can be broadly divided into two types based on the techniques used and the level of knowledge about the software application being tested.
These are known as functional and non-functional testing, and within each category, there are several sub-categories of software testing.
Functional Testing
This type of testing evaluates software application functionality or behavior based on the requirements and specifications of the application.
Functional testing can be performed at various stages of the SDLC to ensure that the application meets the functional requirements and works as expected. Let’s take a look at the various types of functional testing.
Unit Testing
This type of functional testing is conducted at the module or component level. The goal of unit testing is to test individual code modules(or units) to ensure that they are functioning correctly.
Often this is done by software developers during the development phase, and it can be performed manually or with automated testing tools.
Some use cases of unit testing include verifying the correctness of algorithms, testing boundary conditions, and ensuring that the code is working as expected.
The following code snippet is an example of a unit test for an asynchronous JavaScript function that fetches data from the popular JSONPlaceholder API.
This test uses MochaJS and checks whether the function correctly returns the name “Leanne Graham” when given an input of 1. This is the expected result since this is the first name in the users list from the JSONPlaceholder API.
Unit testing code example in JavaScript:
async function fetchUserData(userId) {
const url = `https://jsonplaceholder.typicode.com/users/${userId}`;
const response = await fetch(url);
const data = await response.json();
return data;
}
describe("fetchUserData function", () => {
test("should return the correct user data", async () => {
const userData = await fetchUserData(1);
expect(userData.id).toBe(1);
expect(userData.name).toBe("Leanne Graham");
});
});
White Box Testing
This involves testing the internal workings of the software application, including the code, structure, and design.
Testers with intermediate/advanced programming knowledge perform it. Typically it’s done during the development phase. The objective of white box testing is to ensure that the code functions correctly and identify any code errors.
Integration Testing
This type of functional testing examines the interaction between different modules or components of the software application. The goal here is to ensure components are working correctly when integrated and it can be performed at different levels.
Incremental Testing
This involves integrating components one at a time and testing them as they are integrated. This helps to identify bugs early in the development process as you can tell if a component works correctly before integrating it with other components. There are two ways to go about this.
- Top-Down: Higher-level components are tested first while gradually integrating lower-level modules or components. This helps identify major defects early in the development process and safeguards against critical/major functionalities before moving to lower-level components.
- Bottom-Up: Test lower-level components first and then proceed to integrate the higher-level components. This way, you identify minor defects early in the development process before moving to higher-level components.
Non-incremental Testing
With this approach, you integrate all of the components at once and test them together. This is less efficient than incremental testing because it becomes difficult to identify and debug errors when all the components are integrated at once.
The following example of non-incremental integration testing uses JavaScript, the Mocha.js testing framework, and the Chai assertion library.
This tests an application created with Express.js by ensuring that the root URL (`/`) returns a 200 response code. The second test checks if the page title is correct.
Integration testing code example in JavaScript:
const assert = require('chai').assert;
const request = require('supertest');
const app = require('../app');
describe('Integration Tests', function () {
describe('GET /', function () {
it('should return a 200 response', function (done) {
request(app)
.get('/')
.expect(200, done);
});
it('should return the correct title', function (done) {
request(app)
.get('/')
.end(function (err, res) {
if (err) return done(err);
assert.strictEqual(res.text, '<h1>Hello, world!</h1>');
done();
});
});
});
});
Gray Box Testing
This involves testing the software application with some knowledge of the internal functions and processes. Testers will thus have access to limited information about the software application, such as the database schema, architecture, or algorithm.
Often, you will perform gray box testing during the testing phase of the SDLC.
System Testing
This type of functional testing evaluates the complete software application as a whole. With system testing, the goal is to ensure that the software application meets the functional requirements.
It can be performed manually or using automated tools. Some use cases of system testing include testing the user interface or testing the performance and security of the application.
The following code shows an example of system testing. This JavaScript example uses the Supertest library to make HTTP requests to an application we’re testing.
The first case tests a GET request to `/users` that is expected to return a list of users with the correct properties. The second case tests a POST request that is expected to add a new user with the right properties.
System testing code example in JavaScript:
const assert = require('chai').assert;
const request = require('supertest');
const app = require('../app');
describe('System Tests', function () {
describe('GET /users', function () {
it('should return a list of users', function (done) {
request(app)
.get('/users')
.expect(200)
.end(function (err, res) {
if (err) return done(err);
assert.isArray(res.body, 'response should be an array');
assert.property(res.body[0], 'name', 'user has a name');
assert.property(res.body[0], 'email', 'user has an email');
done();
});
});
});
describe('POST /users', function () {
it('should add a new user', function (done) {
request(app)
.post('/users')
.send({ name: 'John', email: 'john@example.com' })
.expect(201)
.end(function (err, res) {
if (err) return done(err);
assert.property(res.body, 'id', 'user has an id');
assert.equal(res.body.name, 'John', 'user has the correct name');
assert.equal(res.body.email, 'john@example.com', 'correct email');
done();
});
});
});
});
Black Box Testing
This requires no working knowledge of an application’s internal functions or processes. Testers execute predetermined test cases to identify functionality issues rather than internal implementation problems. This is purely focused on inputs and outputs.
Black box testing allows testers to ensure software quality and reliability by simulating how users will interact with it.
End-to-end Testing
This determines the entire flow of an application, starting from the user's initial interaction and going through all the steps until the final output is generated.
It involves testing the application across different systems, servers, and interfaces to ensure all components work together seamlessly and meet the requirements of the stakeholders or customers.
End-to-end testing is often performed to identify integration issues, performance bottlenecks, or functional defects that arise due to the complexity of the application and its various components.
Smoke Testing
This type of software testing evaluates whether the primary or critical features of a software application work as expected and whether the application is stable enough for further testing. This prevents time or resources being wasted on an unstable or faulty situation.
This testing may involve running a series of basic tests on the application, such as launching the application, logging in, and performing simple tasks, to verify that the application is functioning properly.
Sanity Testing
This kind of software testing evaluates new features or changes to check whether they work as expected. Testing may involve running a series of quick tests on the application, such as basic functionality tests or integration tests to verify the new features or changes have not introduced major issues or bugs.
Acceptance Testing
This type of functional testing is used to evaluate whether an application or product meets the stakeholders' or customers' acceptance criteria and requirements.
It involves testing the application on different use cases and verifying it meets the functional and non-functional requirements along with user expectations and needs.
Alpha Testing
This is one of the software testing types in software engineering conducted in-house by developers or testers to evaluate an application before it is released to the public.
It often includes testing the application to identify any issues or bugs and taking corrective actions before the release.
Beta Testing
This is one of the testing types in SDLC conducted by a group of end-users or customers, and it’s completed before an application is released but still in a real environment.
It helps collate information on user experience, functionality, and application performance. Feedback can then be used to identify issues or bugs to improve the user experience.
Non-functional Testing
This testing approach evaluates the non-functional aspects of a software application by assessing things like performance, overall usability, compatibility, security, and reliability. This ensures software applications meet quality standards and work as expected.
Security Testing
Security testing identifies vulnerabilities and threats to a software application. This can include testing for vulnerabilities like SQL Injection, Cross-Site Scripting (XSS), and other security threats.
Security testing is performed via manual and automated testing techniques, which include penetration testing, vulnerability scanning, and code reviews.
Performance Testing
This type of non-functional testing evaluates software application performance under different conditions and can be performed using various techniques, as we’ll now examine.
Load Testing
This evaluates application performance under normal and peak loads. The goal is to ensure the application can handle the expected load without performance issues.
Stress Testing
This is used for checking application performance under extreme loads or conditions. This helps identify application breaking points and checks if it can handle unexpected or abnormal loads.
Scalability Testing
This assesses an application’s ability to handle increased workloads or users. This helps determine if the application can scale up or down as needed to handle varying workloads.
Stability Testing
This is used to figure out how reliable (or stable) an application is over a prolonged period. The objective is to ensure the application can perform consistently over time without performance degradation or failures.
Usability Testing
This type of non-functional testing evaluates how user-friendly and easy-to-use a software application is.
This can involve observing your users as they interact with an application, allowing identification of issues or challenges users may encounter, such as slow response times, difficulty completing tasks, or confusing user interfaces.
Exploratory Testing
This involves testing software without predefined test cases or scripts by exploring and experimenting with an application. This helps identify errors or bugs that were not detected by existing predefined tests while gaining a better understanding of the functionality and performance of an application.
Browser Testing
This testing ensures web applications or websites are compatible with different web browsers, such as Chrome, Firefox, Internet Explorer, Safari, etc.
It includes testing various aspects of the website, such as layout, design, functionality, and performance, across different browsers and devices. This is essential for web-based applications or websites to ensure they are accessible to a wider audience with a consistent user experience.
Accessibility Testing
This type of software testing evaluates the accessibility of an application, ensuring the app is usable for everyone, including those with vision or hearing impairments.
It may involve evaluating the application against accessibility guidelines and standards, such as WCAG (Web Content Accessibility Guidelines), and testing it with assistive technologies like screen readers or magnifiers.
Compatibility Testing
This type of non-functional software testing checks whether an application can function as expected with different hardware, operating systems, browsers, databases, and other software components. This helps to make the application function seamlessly on different platforms to ensure a consistent user experience.
Other Important Types of Software Testing
Beyond the testing types that fall under function or non-functional testing, software testers can also implement several other software testing techniques.
Installation Testing
This is one of those types of testing in software engineering that evaluates whether a software application or product can be installed, upgraded, or uninstalled without any issues or errors.
Testing may involve installing the software on different platforms with varying configurations to identify any installation-related issues, such as missing files or dependencies, installation failures, or conflicts with other applications or software components.
Configuration Testing
This checks whether a software application or product can function as expected on different configurations and setups.
It includes checking software products on different hardware, operating systems, browsers, network configurations, or other software components to identify any configuration-related issues or unexpected behavior or performance.
Recovery Testing
tests whether an application can recover from failures or errors and resume normal operations without data loss or corruption.
Testers do this by simulating different failures, such as hardware or network failures, software crashes, or power outages, and verifying that the application can recover from them and continue functioning as expected. This can help to minimize downtime and data loss in case of failures or errors.
Regression Testing
This type of testing determines whether changes or modifications to a software product have introduced any new issues or bugs or impacted the existing functionality. It’s done by re-running the current tests and test cases on the application to spot new bugs that may have appeared.
User Interface Testing
This is one of the testing types in SDLC that checks the user interface of an application, ensuring it is user-friendly, intuitive, and meets the needs of the target audience.
In this case, testers test the interface across different devices and platforms to ensure that the users can easily navigate and interact with the application. It may also involve testing the visual design, layout, and responsiveness to ensure a consistent and positive user experience.
Ad-Hoc Testing
This is one of the types of testing in software engineering performed without any formal test cases or documentation. Testers usually perform it in an exploratory or free-form manner to identify bugs that were not found via traditional testing.
Ad-Hoc testing is useful in situations where the requirements are unclear, and the testers need to use their expertise and knowledge to identify potential issues.
Backward Compatibility Testing
This tests whether a new software version is compatible with previous versions. This ensures new versions do not break the functionality of older versions and that data and files created with older versions can be used with the new version.
Backward compatibility testing is crucial for software with a large user base, as it ensures that users can continue to use the software without issues.
Agile Testing
This type of software testing follows the same principles as an agile development approach, namely that it’s an iterative and incremental approach and aims to deliver high-quality software quickly.
Agile testing includes continuous testing throughout the development cycle, with frequent testing and feedback loops to ensure software meets customer requirements.
API Testing
This involves testing the Application Programming Interface (API) by testing input/output (I/O), functionality, performance, reliability, and security. API testing is performed with automated testing tools that simulate various scenarios.
Reliability Testing
This determines how stable (or reliable) an application is by testing an application under normal and extreme conditions.
It includes stress, performance, load, and endurance testing. Reliability testing aims to ensure that the software application can function correctly, consistently, and reliably over an extended period.
Conclusion
Software testing is a crucial process that ensures software applications meet the required standards and work as expected. With the increasing complexity of software applications and customer demands, testing has become an indispensable part of the development process.
As a software development professional, a good understanding of different software testing types enables you to identify the appropriate testing approach based on your project's scope, complexity, and specific requirements.
In this article, we’ve covered the different types of software engineering you need to know in 2024. With the help of our guide, you should feel more confident when choosing the correct testing methods for your project.
Want to level up your resume? Check out:
The Best Software Testing Certifications
Frequently Asked Questions
1. What Are the Main Types of Software Testing?
At the highest level, the main types of software testing are manual and automated testing. Manual testing is when human testers execute tests to identify potential errors, while automated testing involves software tools to execute tests.
Beyond these two are many other software testing types, as covered in our guide.
2. How Many Types Are There in Software Testing?
It’s hard to give an exact number for the different types of software testing, as this is an ever-evolving field with new techniques and approaches to software testing being constantly developed. Our guide, however, covers more than 30 types of software testing.
3. What Are the Four Types of Systems Tests?
The four main types of system tests are acceptance testing, system testing, integration testing, and unit testing. Check out the individual sections above for more information on these.
4. What Are the 5 Testing Methods?
The five core testing methods are unit tests, integration/system tests, functional tests, regression tests, and acceptance tests. For more information, check out the individual sections in our guide above.
