Unit testing in software engineering

Unit testing tests each module as an independent component to ensure that it functions correctly and is suitable for assembly/integration with other components. This article explained Unit testing with real lifw examples and its types.It also includes unit testing tools.

Unit testing is a programming language concept that supports the verification and verification of the functionality of applications before creating them. Many consider unit testing to be an essential part of software engineering; however, not all developers are familiar with unit testing concepts and tools. Essentially, not all developers have the ability to test their applications effectively.

Table of contents

• What is Unit testing?
• Why Unit testing?
• Types of Unit testing
• Advantages of Unit testing
• Disadvantages of Unit testing
• Unit Testing Tools
• Conclusion

What is Unit testing?

Unit testing is a crucial practice in software engineering. It’s used to verify the functionality of individual software components. This process is fundamental in the development of large-scale software projects. Not all developers focus on unit testing, even though it’s essential in software creation. This process is typically carried out by developers familiar with the source code being tested. 

As shown in fig that Unit testing is the first step in testing phase followed by integration testing then system testing and at the last acceptance testing.White box and black box testing is done during unit and integration testing.

NOTE: This is the testing that is done at the first step and is done by developers.

lso read: What Does A Software Engineer Do? Roles, Responsibilities, and Skills

Also read: A Day in Life of a Software Engineer – An Interview Log

Also explore: Software Engineer Online Courses & Certifications

Also explore: Free Software Engineer Courses Online

Real life example

1. Suppose a car manufacturer is making a car. He will make different parts like its engine, ignition system, wheels, etc. These different parts are the units that he will test individually. The manufacturer will check if the ignition system and the engine are working fine or not.
2. Suppose the developer is making an e-commerce website. This website has modules like a login page, registration page, cart, payment page, dashboard, etc. The developer will check whether these modules are working fine or not. He will check whether the user can log in from Gmail, yahoo mail, etc. And in the same way for the payment page, he will check whether the user will be able to make payment through Gray, debit card, credit card, or cash on delivery, etc.

Why Unit testing?

It is vital because software developers sometimes try to save time by doing minimal unit testing. This is a myth because wrong unit testing can lead to high costs. Proper unit testing in the early stages of development can save time and money. Unit tests help you fix bugs early in the development cycle and save costs. It helps developers understand the test code base and allows them to make changes quickly. Good unit tests serve as project documentation. Unit tests help reuse code. Migrate both code and tests to the new project. Optimize your code until the test runs again. 

Purpose of Unit testing

• Check code correctness. 
• Test all functions and operations. 
• Fix bugs early in the development cycle and save money. 
• To help developers understand the code base and make changes quickly. 
• Useful for code reuse.

Types of Unit testing

1. Manual Testing

Manual testing is software testing where testers execute test cases manually without using automated tools. Manual testing identifies bugs, problems, and defects in software applications. For example, testers can interpret specific symptoms of a bug and suggest ways to fix it. This is very useful for development. Manual software testing is the most primitive of all testing types and helps find critical bugs in software applications. Manual test example Manual testing has many real-world applications and is especially useful for evaluating usability and accessibility. 

For example, if you’re starting an e-commerce website, you’ll need to make sure:

1. Optimizing for different browsers and devices 
2. hassle-free checkout 
3. Load high-resolution images 
4. Quickly Links to social media channels

2. Automation testing

Automation testing is the process of testing software and other technology products to ensure that they meet stringent requirements. This test ensures that your device or software is working as intended. Test for bugs, defects, and other issues during product development. Various tests, such as regression or functional tests, can be run manually, but automated runs have more advantages. Automated tests can be run at any time of the day. Explore software using script sequences. You can then report what you find and compare that information with previous test runs. Automation developers typically write in ​​C#, JavaScript, and Ruby programming languages. Automated testing has transformed modern software development. This is arguably a significant factor in the explosion of apps over the past decade. Before test automation, all tests should run manually. This was slow, error-prone, and costly.

Also read: Difference between Manual testing and Automation testing

Advantages of Unit testing

1. Catch bugs early

Unit tests catch problems early in the development cycle. This includes errors in the programmer’s implementation and faulty or missing parts of the unit specification. The process of writing a complete suite of tests requires the author to think about input, output, and error conditions, which allows the desired behavior of the Unit to be more clearly defined. 

2. The cost of performing unit testing is low

The cost of finding bugs before you start programming, or when you first write code, is significantly lower than the cost of finding, identifying, and fixing bugs later. 

3. Documentation

Unit tests provide documentationt for your system. Developers who want to learn the functionality provided by the Unit and how to use it can refer to that document to get a basic understanding of the Unit’s user interface.

4. Units can be tested independently

Due to the modular nature of the unit testing, we can test parts of the project without waiting for others to be completed.

5. Changes identified easily

Unit tests allow programmers to refactor code later or update system libraries to ensure that modules still work correctly (for example, regression testing). The procedure is to create test cases for all functions and methods so that you can quickly identify changes that cause errors. Unit tests detect changes that might break the design contract.

Disadvantages of Unit testing

1. Unit testing is problematic if you need to test the user interface (UI). Good if you need to test the implementation of your business logic, but not the UI.
2. It is problematic for product structural design. They solidify the structure of the code. This means that changing it as needed can cause problems.

Unit Testing Tools

1. Junit: Junit is a free testing tool for the Java programming language. Provides assertions to identify test methods. The tool first tests the data before inserting it into your code.

2. NUnit: It is a widely used framework for all .NET languages. This is an open-source tool that allows you to create scripts manually. Supports data-driven tests that can run in parallel. 

3. JMockit: JMockit is an open-source tool. This is a code coverage tool with line and path metrics. This allows you to mock the API using record and verify syntax. This tool provides line coverage, path coverage, and data coverage.

4. EMMA: EMMA is an open-source toolkit for analyzing and reporting on code written in Java. Emma supports coverage types such as method, line, and basic block. Being Java-based, it has no dependencies on external libraries and access to the source code.

5. PHPUnit: PHPUnit is a tool for PHP programmers. Take small pieces of code called units and test each one separately. This tool also allows developers to use predefined assertion methods to ensure that the system behaves in a certain way.

Conclusion

It is an essential practice in software engineering. It greatly increases the efficiency and quality of every new project by helping developers verify new source code functions as intended. Ultimately, everyone involved in software creation should understand how to perform unit testing activities.If you liked this article please share it with your friends and hit the like button.