Who Performs Unit Testing? And Why Is It Necessary?

Who performs unit testing?

Is it done by developers or QA?

Unit testing is a crucial part of software development in many organizations.

The developer performs unit testing. That’s because the unit test provides feedback on whether or not developers have developed new features correctly. The unit tests also tell developers if their latest changes have broken any existing code.

To improve your organization’s efficiency and effectiveness, you need to ensure that your developers know how to do unit testing.

What is unit testing, and why should developers learn it?

Unit testing is the development process of examining unit-of-work for completeness and achieving quality criteria. The scope of unit tests is a single unit of work. The unit of work can be a single method or a class.

Why do you need it?

unit testing

It saves the developer time and prevents testing the same code many times. Unit testing happens during the development phase.

The need for software testing early on keeps developers focused on building one piece at a time. One way to do this is by building the piece of feature and testing it against the specification.

A huge advantage to unit testing is that it ensures you can safely test changes before releasing an application or website into production without adverse impacts on users.

Unit testing also assures that no future changes will disrupt other system parts because all modifications were already tested beforehand. This reduces stress when making changes to the existing codebase.

Who performs unit testing?

Developers perform unit testing.

They are the ones that are responsible for unit testing code to determine if it works or not. Without unit testing, it would be hard to identify issues with your codebase and develop features with confidence. One of the best things about the unit test is that it makes maintenance easy by ensuring that new changes won’t break existing code. It also enables you to focus on writing new features rather than worrying about existing ones.

You can use unit testing as a tool for shorting the time needed for debugging. Testing aims to help the developer find any bugs, errors, or mistakes in the program before releasing it to the public. Programmers should use to break down the program into smaller modules before the process of testing. Testing can help resolve errors.

How do developers write unit tests?

For starters, they use a variety of tools. Developers can use Visual Studio to create and run their automated tests. They can use frameworks like NUnit, MSTest, or xUnit testing framework with a code editor to execute the test code automatically. In addition, there are many third-party frameworks available for C# development, which provide additional functionality not offered by Microsoft’s free framework. Finally, there are open source options such as NDepend, which provides structural analysis on your software design.

Test automation can go a step further with continuous integration (CI). Continuous integration is a development practice that requires programmers to integrate code into the main branch of the source code repository at least once every 24 hours.

CI also requires automated testing, so developers have to write unit tests for their new features. If they don’t, it will be difficult to debug any problems with their code in production. CI reduces the number of bugs in software by ensuring that all changes are tested before being deployed onto a live system.

The role of the developer

The developer has a huge responsibility when it comes to unit testing. Since he performs unit testing, he makes the first step towards a better quality of the application. In addition, a unit test is the last chance for developers to make sure their code is working properly before pushing it for code review and deployment to the test environment.

One way to increase code coverage with unit testing is test driven development. Test driven development is a testing process where you write a unit test case before you write the production code. The idea is to write test cases that define how a unit should be used and then implement it or make changes until all expected results happen, i.e., pass each test case.

If unit testing consists of many steps, you need to break down your unit into smaller modules to keep the process simple and clear for developers.

Advantages of developers testing their code

There are many benefits why developers should test their code:

  1. Unit tests provide a different perspective of how things work, which leads to better understanding and code design. When you write unit tests, they force you to think about your design in smaller testable chunks.
  2. Unit testing leads to a more testable code. This is because they force you to use dependency injection to separate responsibilities between different classes.
  3. Developers can catch errors at a very early stage. The longer you wait to fix a bug, the more expensive it gets to fix it. A bug found during the development takes less time to fix it.
  4. Developers can fix bugs immediately. When you run the tests in the test runner, you get immediate feedback on the quality of your changes. Is everything green? Great. Continue to work. Is something red? No worries, the failing test will pinpoint where the issue is.

Disadvantages of developers testing their code

Writing unit tests for the code you wrote is like being a judge for a murder you committed. The disadvantages are:

  1. Unit testing is not enough and might miss errors. Unit testing is just one tool in a software testing toolbelt. It can’t find errors found during integration. That’s why you need to do integration testing.
  2. Developers only write tests for the cases they can think of. Developers are too familiar with the code, which makes it harder for them to notice mistakes they might have made.

The role of the QA team

Unit testing is a white box testing technique. That means that you perform testing where you know how the software works internally. But only white box testing is not enough.

That’s where QA comes in.

The role of the QA team is to find bugs in the software that unit testing did not find. This is because they have a different view of the software application than developers have. They use a black-box testing technique to verify the application works correctly. The black box technique is a test method where the tester doesn’t know how internally the software works.

When unit testing is done properly before the QA team starts their work, it brings a huge benefit to software projects.

The QA team then verifies results achieved with unit testing through black-box techniques like:

The QA team builds on the foundation that developers have laid out.


You can no longer place all the software testing efforts only on the QA’s shoulders. As software becomes more and more complex, it’s vital to involve as many teams as possible in testing. Only then can you achieve the best results for the business.

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